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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Template Designer Documentation — Jinja2 2.7.2 documentation</title> <link rel="stylesheet" href="_static/jinja.css" type="text/css" /> <link rel="stylesheet" href="_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '', VERSION: '2.7.2', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="_static/jquery.js"></script> <script type="text/javascript" src="_static/underscore.js"></script> <script type="text/javascript" src="_static/doctools.js"></script> <link rel="top" title="Jinja2 2.7.2 documentation" href="index.html" /> <link rel="next" title="Extensions" href="extensions.html" /> <link rel="prev" title="Sandbox" href="sandbox.html" /> </head> <body> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="extensions.html" title="Extensions" accesskey="N">next</a> |</li> <li class="right" > <a href="sandbox.html" title="Sandbox" accesskey="P">previous</a> |</li> <li><a href="index.html">Jinja2 2.7.2 documentation</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="template-designer-documentation"> <h1>Template Designer Documentation<a class="headerlink" href="#template-designer-documentation" title="Permalink to this headline">¶</a></h1> <p>This document describes the syntax and semantics of the template engine and will be most useful as reference to those creating Jinja templates. As the template engine is very flexible the configuration from the application might be slightly different from here in terms of delimiters and behavior of undefined values.</p> <div class="section" id="synopsis"> <h2>Synopsis<a class="headerlink" href="#synopsis" title="Permalink to this headline">¶</a></h2> <p>A template is simply a text file. It can generate any text-based format (HTML, XML, CSV, LaTeX, etc.). It doesn’t have a specific extension, <tt class="docutils literal"><span class="pre">.html</span></tt> or <tt class="docutils literal"><span class="pre">.xml</span></tt> are just fine.</p> <p>A template contains <strong>variables</strong> or <strong>expressions</strong>, which get replaced with values when the template is evaluated, and tags, which control the logic of the template. The template syntax is heavily inspired by Django and Python.</p> <p>Below is a minimal template that illustrates a few basics. We will cover the details later in that document:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp"><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"></span> <span class="nt"><html</span> <span class="na">lang=</span><span class="s">"en"</span><span class="nt">></span> <span class="nt"><head></span> <span class="nt"><title></span>My Webpage<span class="nt"></title></span> <span class="nt"></head></span> <span class="nt"><body></span> <span class="nt"><ul</span> <span class="na">id=</span><span class="s">"navigation"</span><span class="nt">></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">navigation</span> <span class="cp">%}</span> <span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">item.href</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">item.caption</span> <span class="cp">}}</span><span class="nt"></a></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> <span class="nt"><h1></span>My Webpage<span class="nt"></h1></span> <span class="cp">{{</span> <span class="nv">a_variable</span> <span class="cp">}}</span> <span class="nt"></body></span> <span class="nt"></html></span> </pre></div> </div> <p>This covers the default settings. The application developer might have changed the syntax from <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">foo</span> <span class="pre">%}</span></tt> to <tt class="docutils literal"><span class="pre"><%</span> <span class="pre">foo</span> <span class="pre">%></span></tt> or something similar.</p> <p>There are two kinds of delimiters. <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">...</span> <span class="pre">%}</span></tt> and <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">...</span> <span class="pre">}}</span></tt>. The first one is used to execute statements such as for-loops or assign values, the latter prints the result of the expression to the template.</p> </div> <div class="section" id="variables"> <span id="id1"></span><h2>Variables<a class="headerlink" href="#variables" title="Permalink to this headline">¶</a></h2> <p>The application passes variables to the templates you can mess around in the template. Variables may have attributes or elements on them you can access too. How a variable looks like, heavily depends on the application providing those.</p> <p>You can use a dot (<tt class="docutils literal"><span class="pre">.</span></tt>) to access attributes of a variable, alternative the so-called “subscript” syntax (<tt class="docutils literal"><span class="pre">[]</span></tt>) can be used. The following lines do the same:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">foo.bar</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">foo</span><span class="o">[</span><span class="s1">'bar'</span><span class="o">]</span> <span class="cp">}}</span> </pre></div> </div> <p>It’s important to know that the curly braces are <em>not</em> part of the variable but the print statement. If you access variables inside tags don’t put the braces around.</p> <p>If a variable or attribute does not exist you will get back an undefined value. What you can do with that kind of value depends on the application configuration, the default behavior is that it evaluates to an empty string if printed and that you can iterate over it, but every other operation fails.</p> <div class="admonition-implementation admonition" id="notes-on-subscriptions"> <p class="first admonition-title">Implementation</p> <p>For convenience sake <tt class="docutils literal"><span class="pre">foo.bar</span></tt> in Jinja2 does the following things on the Python layer:</p> <ul class="simple"> <li>check if there is an attribute called <cite>bar</cite> on <cite>foo</cite>.</li> <li>if there is not, check if there is an item <tt class="docutils literal"><span class="pre">'bar'</span></tt> in <cite>foo</cite>.</li> <li>if there is not, return an undefined object.</li> </ul> <p><tt class="docutils literal"><span class="pre">foo['bar']</span></tt> on the other hand works mostly the same with the a small difference in the order:</p> <ul class="simple"> <li>check if there is an item <tt class="docutils literal"><span class="pre">'bar'</span></tt> in <cite>foo</cite>.</li> <li>if there is not, check if there is an attribute called <cite>bar</cite> on <cite>foo</cite>.</li> <li>if there is not, return an undefined object.</li> </ul> <p class="last">This is important if an object has an item or attribute with the same name. Additionally there is the <a class="reference internal" href="#attr" title="attr"><tt class="xref py py-func docutils literal"><span class="pre">attr()</span></tt></a> filter that just looks up attributes.</p> </div> </div> <div class="section" id="filters"> <span id="id2"></span><h2>Filters<a class="headerlink" href="#filters" title="Permalink to this headline">¶</a></h2> <p>Variables can be modified by <strong>filters</strong>. Filters are separated from the variable by a pipe symbol (<tt class="docutils literal"><span class="pre">|</span></tt>) and may have optional arguments in parentheses. Multiple filters can be chained. The output of one filter is applied to the next.</p> <p><tt class="docutils literal"><span class="pre">{{</span> <span class="pre">name|striptags|title</span> <span class="pre">}}</span></tt> for example will remove all HTML Tags from the <cite>name</cite> and title-cases it. Filters that accept arguments have parentheses around the arguments, like a function call. This example will join a list by commas: <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">list|join(',</span> <span class="pre">')</span> <span class="pre">}}</span></tt>.</p> <p>The <a class="reference internal" href="#builtin-filters"><em>List of Builtin Filters</em></a> below describes all the builtin filters.</p> </div> <div class="section" id="tests"> <span id="id3"></span><h2>Tests<a class="headerlink" href="#tests" title="Permalink to this headline">¶</a></h2> <p>Beside filters there are also so called “tests” available. Tests can be used to test a variable against a common expression. To test a variable or expression you add <cite>is</cite> plus the name of the test after the variable. For example to find out if a variable is defined you can do <tt class="docutils literal"><span class="pre">name</span> <span class="pre">is</span> <span class="pre">defined</span></tt> which will then return true or false depending on if <cite>name</cite> is defined.</p> <p>Tests can accept arguments too. If the test only takes one argument you can leave out the parentheses to group them. For example the following two expressions do the same:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">if</span> <span class="nb">loop</span><span class="nv">.index</span> <span class="k">is</span> <span class="nf">divisibleby</span> <span class="m">3</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">if</span> <span class="nb">loop</span><span class="nv">.index</span> <span class="k">is</span> <span class="nf">divisibleby</span><span class="o">(</span><span class="m">3</span><span class="o">)</span> <span class="cp">%}</span> </pre></div> </div> <p>The <a class="reference internal" href="#builtin-tests"><em>List of Builtin Tests</em></a> below describes all the builtin tests.</p> </div> <div class="section" id="comments"> <h2>Comments<a class="headerlink" href="#comments" title="Permalink to this headline">¶</a></h2> <p>To comment-out part of a line in a template, use the comment syntax which is by default set to <tt class="docutils literal"><span class="pre">{#</span> <span class="pre">...</span> <span class="pre">#}</span></tt>. This is useful to comment out parts of the template for debugging or to add information for other template designers or yourself:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="c">{# note: disabled template because we no longer use this</span> <span class="c"> {% for user in users %}</span> <span class="c"> ...</span> <span class="c"> {% endfor %}</span> <span class="c">#}</span> </pre></div> </div> </div> <div class="section" id="whitespace-control"> <h2>Whitespace Control<a class="headerlink" href="#whitespace-control" title="Permalink to this headline">¶</a></h2> <p>In the default configuration, a single trailing newline is stripped if present, and whitespace is not further modified by the template engine. Each whitespace (spaces, tabs, newlines etc.) is returned unchanged. If the application configures Jinja to <cite>trim_blocks</cite> the first newline after a template tag is removed automatically (like in PHP). The <cite>lstrip_blocks</cite> option can also be set to strip tabs and spaces from the beginning of line to the start of a block. (Nothing will be stripped if there are other characters before the start of the block.)</p> <p>With both <cite>trim_blocks</cite> and <cite>lstrip_blocks</cite> enabled you can put block tags on their own lines, and the entire block line will be removed when rendered, preserving the whitespace of the contents. For example, without the <cite>trim_blocks</cite> and <cite>lstrip_blocks</cite> options, this template:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><div></span> <span class="cp">{%</span> <span class="k">if</span> <span class="kp">True</span> <span class="cp">%}</span> yay <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> <span class="nt"></div></span> </pre></div> </div> <p>gets rendered with blank lines inside the div:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><div></span> yay <span class="nt"></div></span> </pre></div> </div> <p>But with both <cite>trim_blocks</cite> and <cite>lstrip_blocks</cite> enabled, the lines with the template blocks are removed while preserving the whitespace of the contents:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><div></span> yay <span class="nt"></div></span> </pre></div> </div> <p>You can manually disable the <cite>lstrip_blocks</cite> behavior by putting a plus sign (<tt class="docutils literal"><span class="pre">+</span></tt>) at the start of a block:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><div></span> {%+ if something %}yay<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> <span class="nt"></div></span> </pre></div> </div> <p>You can also strip whitespace in templates by hand. If you put an minus sign (<tt class="docutils literal"><span class="pre">-</span></tt>) to the start or end of an block (for example a for tag), a comment or variable expression you can remove the whitespaces after or before that block:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">seq</span> -<span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">item</span> <span class="cp">}}</span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>This will yield all elements without whitespace between them. If <cite>seq</cite> was a list of numbers from <tt class="docutils literal"><span class="pre">1</span></tt> to <tt class="docutils literal"><span class="pre">9</span></tt> the output would be <tt class="docutils literal"><span class="pre">123456789</span></tt>.</p> <p>If <a class="reference internal" href="#line-statements"><em>Line Statements</em></a> are enabled they strip leading whitespace automatically up to the beginning of the line.</p> <p>Jinja2 by default also removes trailing newlines. To keep the single trailing newline when it is present, configure Jinja to <cite>keep_trailing_newline</cite>.</p> <div class="admonition-note admonition"> <p class="first admonition-title">Note</p> <p>You must not use a whitespace between the tag and the minus sign.</p> <p><strong>valid</strong>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span>- <span class="k">if</span> <span class="nv">foo</span> -<span class="cp">%}</span>...<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> </pre></div> </div> <p><strong>invalid</strong>:</p> <div class="last highlight-html+jinja"><div class="highlight"><pre>{% - if foo - %}...<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> </pre></div> </div> </div> </div> <div class="section" id="escaping"> <h2>Escaping<a class="headerlink" href="#escaping" title="Permalink to this headline">¶</a></h2> <p>It is sometimes desirable or even necessary to have Jinja ignore parts it would otherwise handle as variables or blocks. For example if the default syntax is used and you want to use <tt class="docutils literal"><span class="pre">{{</span></tt> as raw string in the template and not start a variable you have to use a trick.</p> <p>The easiest way is to output the variable delimiter (<tt class="docutils literal"><span class="pre">{{</span></tt>) by using a variable expression:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="s1">'{{'</span> <span class="cp">}}</span> </pre></div> </div> <p>For bigger sections it makes sense to mark a block <cite>raw</cite>. For example to put Jinja syntax as example into a template you can use this snippet:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">raw</span> <span class="cp">%}</span> <ul> {% for item in seq %} <li>{{ item }}</li> {% endfor %} </ul> <span class="cp">{%</span> <span class="k">endraw</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="line-statements"> <span id="id4"></span><h2>Line Statements<a class="headerlink" href="#line-statements" title="Permalink to this headline">¶</a></h2> <p>If line statements are enabled by the application it’s possible to mark a line as a statement. For example if the line statement prefix is configured to <tt class="docutils literal"><span class="pre">#</span></tt> the following two examples are equivalent:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> # for item in seq <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">item</span> <span class="cp">}}</span><span class="nt"></li></span> # endfor <span class="nt"></ul></span> <span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">seq</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">item</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>The line statement prefix can appear anywhere on the line as long as no text precedes it. For better readability statements that start a block (such as <cite>for</cite>, <cite>if</cite>, <cite>elif</cite> etc.) may end with a colon:</p> <div class="highlight-html+jinja"><div class="highlight"><pre># for item in seq: ... # endfor </pre></div> </div> <div class="admonition-note admonition"> <p class="first admonition-title">Note</p> <p>Line statements can span multiple lines if there are open parentheses, braces or brackets:</p> <div class="last highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> # for href, caption in [('index.html', 'Index'), ('about.html', 'About')]: <span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">href</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">caption</span> <span class="cp">}}</span><span class="nt"></a></li></span> # endfor <span class="nt"></ul></span> </pre></div> </div> </div> <p>Since Jinja 2.2 line-based comments are available as well. For example if the line-comment prefix is configured to be <tt class="docutils literal"><span class="pre">##</span></tt> everything from <tt class="docutils literal"><span class="pre">##</span></tt> to the end of the line is ignored (excluding the newline sign):</p> <div class="highlight-html+jinja"><div class="highlight"><pre># for item in seq: <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">item</span> <span class="cp">}}</span><span class="nt"></li></span> ## this comment is ignored # endfor </pre></div> </div> </div> <div class="section" id="template-inheritance"> <span id="id5"></span><h2>Template Inheritance<a class="headerlink" href="#template-inheritance" title="Permalink to this headline">¶</a></h2> <p>The most powerful part of Jinja is template inheritance. Template inheritance allows you to build a base “skeleton” template that contains all the common elements of your site and defines <strong>blocks</strong> that child templates can override.</p> <p>Sounds complicated but is very basic. It’s easiest to understand it by starting with an example.</p> <div class="section" id="base-template"> <h3>Base Template<a class="headerlink" href="#base-template" title="Permalink to this headline">¶</a></h3> <p>This template, which we’ll call <tt class="docutils literal"><span class="pre">base.html</span></tt>, defines a simple HTML skeleton document that you might use for a simple two-column page. It’s the job of “child” templates to fill the empty blocks with content:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp"><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"></span> <span class="nt"><html</span> <span class="na">lang=</span><span class="s">"en"</span><span class="nt">></span> <span class="nt"><html</span> <span class="na">xmlns=</span><span class="s">"http://www.w3.org/1999/xhtml"</span><span class="nt">></span> <span class="nt"><head></span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">head</span> <span class="cp">%}</span> <span class="nt"><link</span> <span class="na">rel=</span><span class="s">"stylesheet"</span> <span class="na">href=</span><span class="s">"style.css"</span> <span class="nt">/></span> <span class="nt"><title></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span> - My Webpage<span class="nt"></title></span> <span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> <span class="nt"></head></span> <span class="nt"><body></span> <span class="nt"><div</span> <span class="na">id=</span><span class="s">"content"</span><span class="nt">></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="nt"></div></span> <span class="nt"><div</span> <span class="na">id=</span><span class="s">"footer"</span><span class="nt">></span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">footer</span> <span class="cp">%}</span> <span class="ni">&copy;</span> Copyright 2008 by <span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://domain.invalid/"</span><span class="nt">></span>you<span class="nt"></a></span>. <span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> <span class="nt"></div></span> <span class="nt"></body></span> </pre></div> </div> <p>In this example, the <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">%}</span></tt> tags define four blocks that child templates can fill in. All the <cite>block</cite> tag does is to tell the template engine that a child template may override those portions of the template.</p> </div> <div class="section" id="child-template"> <h3>Child Template<a class="headerlink" href="#child-template" title="Permalink to this headline">¶</a></h3> <p>A child template might look like this:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">extends</span> <span class="s2">"base.html"</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>Index<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">head</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nb">super</span><span class="o">()</span> <span class="cp">}}</span> <span class="nt"><style </span><span class="na">type=</span><span class="s">"text/css"</span><span class="nt">></span> <span class="nc">.important</span> <span class="p">{</span> <span class="k">color</span><span class="o">:</span> <span class="m">#336699</span><span class="p">;</span> <span class="p">}</span> <span class="nt"></style></span> <span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}</span> <span class="nt"><h1></span>Index<span class="nt"></h1></span> <span class="nt"><p</span> <span class="na">class=</span><span class="s">"important"</span><span class="nt">></span> Welcome on my awesome homepage. <span class="nt"></p></span> <span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> </pre></div> </div> <p>The <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">extends</span> <span class="pre">%}</span></tt> tag is the key here. It tells the template engine that this template “extends” another template. When the template system evaluates this template, first it locates the parent. The extends tag should be the first tag in the template. Everything before it is printed out normally and may cause confusion. For details about this behavior and how to take advantage of it, see <a class="reference internal" href="tricks.html#null-master-fallback"><em>Null-Master Fallback</em></a>.</p> <p>The filename of the template depends on the template loader. For example the <tt class="xref py py-class docutils literal"><span class="pre">FileSystemLoader</span></tt> allows you to access other templates by giving the filename. You can access templates in subdirectories with a slash:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">extends</span> <span class="s2">"layout/default.html"</span> <span class="cp">%}</span> </pre></div> </div> <p>But this behavior can depend on the application embedding Jinja. Note that since the child template doesn’t define the <tt class="docutils literal"><span class="pre">footer</span></tt> block, the value from the parent template is used instead.</p> <p>You can’t define multiple <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">%}</span></tt> tags with the same name in the same template. This limitation exists because a block tag works in “both” directions. That is, a block tag doesn’t just provide a hole to fill - it also defines the content that fills the hole in the <em>parent</em>. If there were two similarly-named <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">%}</span></tt> tags in a template, that template’s parent wouldn’t know which one of the blocks’ content to use.</p> <p>If you want to print a block multiple times you can however use the special <cite>self</cite> variable and call the block with that name:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><title></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="nt"></title></span> <span class="nt"><h1></span><span class="cp">{{</span> <span class="nv">self.title</span><span class="o">()</span> <span class="cp">}}</span><span class="nt"></h1></span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">body</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="super-blocks"> <h3>Super Blocks<a class="headerlink" href="#super-blocks" title="Permalink to this headline">¶</a></h3> <p>It’s possible to render the contents of the parent block by calling <cite>super</cite>. This gives back the results of the parent block:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">block</span> <span class="nv">sidebar</span> <span class="cp">%}</span> <span class="nt"><h3></span>Table Of Contents<span class="nt"></h3></span> ... <span class="cp">{{</span> <span class="nb">super</span><span class="o">()</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="named-block-end-tags"> <h3>Named Block End-Tags<a class="headerlink" href="#named-block-end-tags" title="Permalink to this headline">¶</a></h3> <p>Jinja2 allows you to put the name of the block after the end tag for better readability:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">block</span> <span class="nv">sidebar</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">block</span> <span class="nv">inner_sidebar</span> <span class="cp">%}</span> ... <span class="cp">{%</span> <span class="k">endblock</span> <span class="nv">inner_sidebar</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">endblock</span> <span class="nv">sidebar</span> <span class="cp">%}</span> </pre></div> </div> <p>However the name after the <cite>endblock</cite> word must match the block name.</p> </div> <div class="section" id="block-nesting-and-scope"> <h3>Block Nesting and Scope<a class="headerlink" href="#block-nesting-and-scope" title="Permalink to this headline">¶</a></h3> <p>Blocks can be nested for more complex layouts. However per default blocks may not access variables from outer scopes:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">seq</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">loop_item</span> <span class="cp">%}{{</span> <span class="nv">item</span> <span class="cp">}}{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>This example would output empty <tt class="docutils literal"><span class="pre"><li></span></tt> items because <cite>item</cite> is unavailable inside the block. The reason for this is that if the block is replaced by a child template a variable would appear that was not defined in the block or passed to the context.</p> <p>Starting with Jinja 2.2 you can explicitly specify that variables are available in a block by setting the block to “scoped” by adding the <cite>scoped</cite> modifier to a block declaration:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">seq</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">loop_item</span> <span class="k">scoped</span> <span class="cp">%}{{</span> <span class="nv">item</span> <span class="cp">}}{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>When overriding a block the <cite>scoped</cite> modifier does not have to be provided.</p> </div> <div class="section" id="template-objects"> <h3>Template Objects<a class="headerlink" href="#template-objects" title="Permalink to this headline">¶</a></h3> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.4.</span></p> <p>If a template object was passed to the template context you can extend from that object as well. Assuming the calling code passes a layout template as <cite>layout_template</cite> to the environment, this code works:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">extends</span> <span class="nv">layout_template</span> <span class="cp">%}</span> </pre></div> </div> <p>Previously the <cite>layout_template</cite> variable had to be a string with the layout template’s filename for this to work.</p> </div> </div> <div class="section" id="html-escaping"> <h2>HTML Escaping<a class="headerlink" href="#html-escaping" title="Permalink to this headline">¶</a></h2> <p>When generating HTML from templates, there’s always a risk that a variable will include characters that affect the resulting HTML. There are two approaches: manually escaping each variable or automatically escaping everything by default.</p> <p>Jinja supports both, but what is used depends on the application configuration. The default configuaration is no automatic escaping for various reasons:</p> <ul class="simple"> <li>escaping everything except of safe values will also mean that Jinja is escaping variables known to not include HTML such as numbers which is a huge performance hit.</li> <li>The information about the safety of a variable is very fragile. It could happen that by coercing safe and unsafe values the return value is double escaped HTML.</li> </ul> <div class="section" id="working-with-manual-escaping"> <h3>Working with Manual Escaping<a class="headerlink" href="#working-with-manual-escaping" title="Permalink to this headline">¶</a></h3> <p>If manual escaping is enabled it’s <strong>your</strong> responsibility to escape variables if needed. What to escape? If you have a variable that <em>may</em> include any of the following chars (<tt class="docutils literal"><span class="pre">></span></tt>, <tt class="docutils literal"><span class="pre"><</span></tt>, <tt class="docutils literal"><span class="pre">&</span></tt>, or <tt class="docutils literal"><span class="pre">"</span></tt>) you <strong>have to</strong> escape it unless the variable contains well-formed and trusted HTML. Escaping works by piping the variable through the <tt class="docutils literal"><span class="pre">|e</span></tt> filter: <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">user.username|e</span> <span class="pre">}}</span></tt>.</p> </div> <div class="section" id="working-with-automatic-escaping"> <h3>Working with Automatic Escaping<a class="headerlink" href="#working-with-automatic-escaping" title="Permalink to this headline">¶</a></h3> <p>When automatic escaping is enabled everything is escaped by default except for values explicitly marked as safe. Those can either be marked by the application or in the template by using the <cite>|safe</cite> filter. The main problem with this approach is that Python itself doesn’t have the concept of tainted values so the information if a value is safe or unsafe can get lost. If the information is lost escaping will take place which means that you could end up with double escaped contents.</p> <p>Double escaping is easy to avoid however, just rely on the tools Jinja2 provides and don’t use builtin Python constructs such as the string modulo operator.</p> <p>Functions returning template data (macros, <cite>super</cite>, <cite>self.BLOCKNAME</cite>) return safe markup always.</p> <p>String literals in templates with automatic escaping are considered unsafe too. The reason for this is that the safe string is an extension to Python and not every library will work properly with it.</p> </div> </div> <div class="section" id="list-of-control-structures"> <h2>List of Control Structures<a class="headerlink" href="#list-of-control-structures" title="Permalink to this headline">¶</a></h2> <p>A control structure refers to all those things that control the flow of a program - conditionals (i.e. if/elif/else), for-loops, as well as things like macros and blocks. Control structures appear inside <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">...</span> <span class="pre">%}</span></tt> blocks in the default syntax.</p> <div class="section" id="for"> <h3>For<a class="headerlink" href="#for" title="Permalink to this headline">¶</a></h3> <p>Loop over each item in a sequence. For example, to display a list of users provided in a variable called <cite>users</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><h1></span>Members<span class="nt"></h1></span> <span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">user.username</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>As variables in templates retain their object properties, it is possible to iterate over containers like <cite>dict</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><dl></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">key</span><span class="o">,</span> <span class="nv">value</span> <span class="k">in</span> <span class="nv">my_dict.iteritems</span><span class="o">()</span> <span class="cp">%}</span> <span class="nt"><dt></span><span class="cp">{{</span> <span class="nv">key</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></dt></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">value</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></dl></span> </pre></div> </div> <p>Note however that dictionaries usually are unordered so you might want to either pass it as a sorted list to the template or use the <cite>dictsort</cite> filter.</p> <p>Inside of a for-loop block you can access some special variables:</p> <table border="1" class="docutils"> <colgroup> <col width="31%" /> <col width="69%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Variable</th> <th class="head">Description</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><cite>loop.index</cite></td> <td>The current iteration of the loop. (1 indexed)</td> </tr> <tr class="row-odd"><td><cite>loop.index0</cite></td> <td>The current iteration of the loop. (0 indexed)</td> </tr> <tr class="row-even"><td><cite>loop.revindex</cite></td> <td>The number of iterations from the end of the loop (1 indexed)</td> </tr> <tr class="row-odd"><td><cite>loop.revindex0</cite></td> <td>The number of iterations from the end of the loop (0 indexed)</td> </tr> <tr class="row-even"><td><cite>loop.first</cite></td> <td>True if first iteration.</td> </tr> <tr class="row-odd"><td><cite>loop.last</cite></td> <td>True if last iteration.</td> </tr> <tr class="row-even"><td><cite>loop.length</cite></td> <td>The number of items in the sequence.</td> </tr> <tr class="row-odd"><td><cite>loop.cycle</cite></td> <td>A helper function to cycle between a list of sequences. See the explanation below.</td> </tr> <tr class="row-even"><td><cite>loop.depth</cite></td> <td>Indicates how deep in deep in a recursive loop the rendering currently is. Starts at level 1</td> </tr> <tr class="row-odd"><td><a href="#id6"><span class="problematic" id="id7">`</span></a>loop.depth0</td> <td>Indicates how deep in deep in a recursive loop the rendering currently is. Starts at level 0</td> </tr> </tbody> </table> <p>Within a for-loop, it’s possible to cycle among a list of strings/variables each time through the loop by using the special <cite>loop.cycle</cite> helper:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">row</span> <span class="k">in</span> <span class="nv">rows</span> <span class="cp">%}</span> <span class="nt"><li</span> <span class="na">class=</span><span class="s">"</span><span class="cp">{{</span> <span class="nb">loop</span><span class="nv">.cycle</span><span class="o">(</span><span class="s1">'odd'</span><span class="o">,</span> <span class="s1">'even'</span><span class="o">)</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">row</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>Since Jinja 2.1 an extra <cite>cycle</cite> helper exists that allows loop-unbound cycling. For more information have a look at the <a class="reference internal" href="#builtin-globals"><em>List of Global Functions</em></a>.</p> <p id="loop-filtering">Unlike in Python it’s not possible to <cite>break</cite> or <cite>continue</cite> in a loop. You can however filter the sequence during iteration which allows you to skip items. The following example skips all the users which are hidden:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="k">if</span> <span class="k">not</span> <span class="nv">user.hidden</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">user.username</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>The advantage is that the special <cite>loop</cite> variable will count correctly thus not counting the users not iterated over.</p> <p>If no iteration took place because the sequence was empty or the filtering removed all the items from the sequence you can render a replacement block by using <cite>else</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">user.username</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">else</span> <span class="cp">%}</span> <span class="nt"><li><em></span>no users found<span class="nt"></em></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>Note that in Python <cite>else</cite> blocks are executed whenever the corresponding loop did not <cite>break</cite>. Since in Jinja loops cannot <cite>break</cite> anyway, a slightly different behavior of the <cite>else</cite> keyword was chosen.</p> <p>It is also possible to use loops recursively. This is useful if you are dealing with recursive data such as sitemaps. To use loops recursively you basically have to add the <cite>recursive</cite> modifier to the loop definition and call the <cite>loop</cite> variable with the new iterable where you want to recurse.</p> <p>The following example implements a sitemap with recursive loops:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul</span> <span class="na">class=</span><span class="s">"sitemap"</span><span class="nt">></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">sitemap</span> <span class="k">recursive</span> <span class="cp">%}</span> <span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">item.href</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">item.title</span> <span class="cp">}}</span><span class="nt"></a></span> <span class="cp">{%</span>- <span class="k">if</span> <span class="nv">item.children</span> -<span class="cp">%}</span> <span class="nt"><ul</span> <span class="na">class=</span><span class="s">"submenu"</span><span class="nt">></span><span class="cp">{{</span> <span class="nb">loop</span><span class="o">(</span><span class="nv">item.children</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></ul></span> <span class="cp">{%</span>- <span class="k">endif</span> <span class="cp">%}</span><span class="nt"></li></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>The <cite>loop</cite> variable always refers to the closest (innermost) loop. If we have more than one levels of loops, we can rebind the variable <cite>loop</cite> by writing <cite>{% set outer_loop = loop %}</cite> after the loop that we want to use recursively. Then, we can call it using <cite>{{ outer_loop(...) }}</cite></p> </div> <div class="section" id="if"> <h3>If<a class="headerlink" href="#if" title="Permalink to this headline">¶</a></h3> <p>The <cite>if</cite> statement in Jinja is comparable with the if statements of Python. In the simplest form you can use it to test if a variable is defined, not empty or not false:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">if</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">user.username</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> </pre></div> </div> <p>For multiple branches <cite>elif</cite> and <cite>else</cite> can be used like in Python. You can use more complex <a class="reference internal" href="#expressions"><em>Expressions</em></a> there too:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">if</span> <span class="nv">kenny.sick</span> <span class="cp">%}</span> Kenny is sick. <span class="cp">{%</span> <span class="k">elif</span> <span class="nv">kenny.dead</span> <span class="cp">%}</span> You killed Kenny! You bastard!!! <span class="cp">{%</span> <span class="k">else</span> <span class="cp">%}</span> Kenny looks okay --- so far <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> </pre></div> </div> <p>If can also be used as <a class="reference internal" href="#if-expression"><em>inline expression</em></a> and for <a class="reference internal" href="#loop-filtering"><em>loop filtering</em></a>.</p> </div> <div class="section" id="macros"> <h3>Macros<a class="headerlink" href="#macros" title="Permalink to this headline">¶</a></h3> <p>Macros are comparable with functions in regular programming languages. They are useful to put often used idioms into reusable functions to not repeat yourself.</p> <p>Here a small example of a macro that renders a form element:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">macro</span> <span class="nv">input</span><span class="o">(</span><span class="nv">name</span><span class="o">,</span> <span class="nv">value</span><span class="o">=</span><span class="s1">''</span><span class="o">,</span> <span class="nv">type</span><span class="o">=</span><span class="s1">'text'</span><span class="o">,</span> <span class="nv">size</span><span class="o">=</span><span class="m">20</span><span class="o">)</span> -<span class="cp">%}</span> <span class="nt"><input</span> <span class="na">type=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">type</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">name=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">value=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">value</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">size=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">size</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span> <span class="cp">{%</span>- <span class="k">endmacro</span> <span class="cp">%}</span> </pre></div> </div> <p>The macro can then be called like a function in the namespace:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><p></span><span class="cp">{{</span> <span class="nv">input</span><span class="o">(</span><span class="s1">'username'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></p></span> <span class="nt"><p></span><span class="cp">{{</span> <span class="nv">input</span><span class="o">(</span><span class="s1">'password'</span><span class="o">,</span> <span class="nv">type</span><span class="o">=</span><span class="s1">'password'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></p></span> </pre></div> </div> <p>If the macro was defined in a different template you have to <a class="reference internal" href="#import"><em>import</em></a> it first.</p> <p>Inside macros you have access to three special variables:</p> <dl class="docutils"> <dt><cite>varargs</cite></dt> <dd>If more positional arguments are passed to the macro than accepted by the macro they end up in the special <cite>varargs</cite> variable as list of values.</dd> <dt><cite>kwargs</cite></dt> <dd>Like <cite>varargs</cite> but for keyword arguments. All unconsumed keyword arguments are stored in this special variable.</dd> <dt><cite>caller</cite></dt> <dd>If the macro was called from a <a class="reference internal" href="#call"><em>call</em></a> tag the caller is stored in this variable as macro which can be called.</dd> </dl> <p>Macros also expose some of their internal details. The following attributes are available on a macro object:</p> <dl class="docutils"> <dt><cite>name</cite></dt> <dd>The name of the macro. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">input.name</span> <span class="pre">}}</span></tt> will print <tt class="docutils literal"><span class="pre">input</span></tt>.</dd> <dt><cite>arguments</cite></dt> <dd>A tuple of the names of arguments the macro accepts.</dd> <dt><cite>defaults</cite></dt> <dd>A tuple of default values.</dd> <dt><cite>catch_kwargs</cite></dt> <dd>This is <cite>true</cite> if the macro accepts extra keyword arguments (ie: accesses the special <cite>kwargs</cite> variable).</dd> <dt><cite>catch_varargs</cite></dt> <dd>This is <cite>true</cite> if the macro accepts extra positional arguments (ie: accesses the special <cite>varargs</cite> variable).</dd> <dt><cite>caller</cite></dt> <dd>This is <cite>true</cite> if the macro accesses the special <cite>caller</cite> variable and may be called from a <a class="reference internal" href="#call"><em>call</em></a> tag.</dd> </dl> <p>If a macro name starts with an underscore it’s not exported and can’t be imported.</p> </div> <div class="section" id="call"> <span id="id8"></span><h3>Call<a class="headerlink" href="#call" title="Permalink to this headline">¶</a></h3> <p>In some cases it can be useful to pass a macro to another macro. For this purpose you can use the special <cite>call</cite> block. The following example shows a macro that takes advantage of the call functionality and how it can be used:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">macro</span> <span class="nv">render_dialog</span><span class="o">(</span><span class="nv">title</span><span class="o">,</span> <span class="nv">class</span><span class="o">=</span><span class="s1">'dialog'</span><span class="o">)</span> -<span class="cp">%}</span> <span class="nt"><div</span> <span class="na">class=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">class</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span> <span class="nt"><h2></span><span class="cp">{{</span> <span class="nv">title</span> <span class="cp">}}</span><span class="nt"></h2></span> <span class="nt"><div</span> <span class="na">class=</span><span class="s">"contents"</span><span class="nt">></span> <span class="cp">{{</span> <span class="nv">caller</span><span class="o">()</span> <span class="cp">}}</span> <span class="nt"></div></span> <span class="nt"></div></span> <span class="cp">{%</span>- <span class="k">endmacro</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">call</span> <span class="nv">render_dialog</span><span class="o">(</span><span class="s1">'Hello World'</span><span class="o">)</span> <span class="cp">%}</span> This is a simple dialog rendered by using a macro and a call block. <span class="cp">{%</span> <span class="k">endcall</span> <span class="cp">%}</span> </pre></div> </div> <p>It’s also possible to pass arguments back to the call block. This makes it useful as replacement for loops. Generally speaking a call block works exactly like an macro, just that it doesn’t have a name.</p> <p>Here an example of how a call block can be used with arguments:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">macro</span> <span class="nv">dump_users</span><span class="o">(</span><span class="nv">users</span><span class="o">)</span> -<span class="cp">%}</span> <span class="nt"><ul></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><li><p></span><span class="cp">{{</span> <span class="nv">user.username</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></p></span><span class="cp">{{</span> <span class="nv">caller</span><span class="o">(</span><span class="nv">user</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> <span class="cp">{%</span>- <span class="k">endmacro</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">call</span><span class="o">(</span><span class="nv">user</span><span class="o">)</span> <span class="nv">dump_users</span><span class="o">(</span><span class="nv">list_of_user</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><dl></span> <span class="nt"><dl></span>Realname<span class="nt"></dl></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">user.realname</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"><dl></span>Description<span class="nt"></dl></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">user.description</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"></dl></span> <span class="cp">{%</span> <span class="k">endcall</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="id9"> <h3>Filters<a class="headerlink" href="#id9" title="Permalink to this headline">¶</a></h3> <p>Filter sections allow you to apply regular Jinja2 filters on a block of template data. Just wrap the code in the special <cite>filter</cite> section:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">filter</span> <span class="nf">upper</span> <span class="cp">%}</span> This text becomes uppercase <span class="cp">{%</span> <span class="k">endfilter</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="assignments"> <h3>Assignments<a class="headerlink" href="#assignments" title="Permalink to this headline">¶</a></h3> <p>Inside code blocks you can also assign values to variables. Assignments at top level (outside of blocks, macros or loops) are exported from the template like top level macros and can be imported by other templates.</p> <p>Assignments use the <cite>set</cite> tag and can have multiple targets:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">set</span> <span class="nv">navigation</span> <span class="o">=</span> <span class="o">[(</span><span class="s1">'index.html'</span><span class="o">,</span> <span class="s1">'Index'</span><span class="o">),</span> <span class="o">(</span><span class="s1">'about.html'</span><span class="o">,</span> <span class="s1">'About'</span><span class="o">)]</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">set</span> <span class="nv">key</span><span class="o">,</span> <span class="nv">value</span> <span class="o">=</span> <span class="nv">call_something</span><span class="o">()</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="extends"> <h3>Extends<a class="headerlink" href="#extends" title="Permalink to this headline">¶</a></h3> <p>The <cite>extends</cite> tag can be used to extend a template from another one. You can have multiple of them in a file but only one of them may be executed at the time. See the section about <a class="reference internal" href="#template-inheritance"><em>Template Inheritance</em></a> above.</p> </div> <div class="section" id="block"> <h3>Block<a class="headerlink" href="#block" title="Permalink to this headline">¶</a></h3> <p>Blocks are used for inheritance and act as placeholders and replacements at the same time. They are documented in detail as part of the section about <a class="reference internal" href="#template-inheritance"><em>Template Inheritance</em></a>.</p> </div> <div class="section" id="include"> <h3>Include<a class="headerlink" href="#include" title="Permalink to this headline">¶</a></h3> <p>The <cite>include</cite> statement is useful to include a template and return the rendered contents of that file into the current namespace:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">include</span> <span class="s1">'header.html'</span> <span class="cp">%}</span> Body <span class="cp">{%</span> <span class="k">include</span> <span class="s1">'footer.html'</span> <span class="cp">%}</span> </pre></div> </div> <p>Included templates have access to the variables of the active context by default. For more details about context behavior of imports and includes see <a class="reference internal" href="#import-visibility"><em>Import Context Behavior</em></a>.</p> <p>From Jinja 2.2 onwards you can mark an include with <tt class="docutils literal"><span class="pre">ignore</span> <span class="pre">missing</span></tt> in which case Jinja will ignore the statement if the template to be included does not exist. When combined with <tt class="docutils literal"><span class="pre">with</span></tt> or <tt class="docutils literal"><span class="pre">without</span> <span class="pre">context</span></tt> it has to be placed <em>before</em> the context visibility statement. Here some valid examples:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">include</span> <span class="s2">"sidebar.html"</span> <span class="k">ignore missing</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">include</span> <span class="s2">"sidebar.html"</span> <span class="k">ignore missing</span> <span class="k">with context</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">include</span> <span class="s2">"sidebar.html"</span> <span class="k">ignore missing</span> <span class="k">without context</span> <span class="cp">%}</span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> <p>You can also provide a list of templates that are checked for existence before inclusion. The first template that exists will be included. If <cite>ignore missing</cite> is given, it will fall back to rendering nothing if none of the templates exist, otherwise it will raise an exception.</p> <p>Example:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">include</span> <span class="o">[</span><span class="s1">'page_detailed.html'</span><span class="o">,</span> <span class="s1">'page.html'</span><span class="o">]</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">include</span> <span class="o">[</span><span class="s1">'special_sidebar.html'</span><span class="o">,</span> <span class="s1">'sidebar.html'</span><span class="o">]</span> <span class="k">ignore missing</span> <span class="cp">%}</span> </pre></div> </div> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.4: </span>If a template object was passed to the template context you can include that object using <cite>include</cite>.</p> </div> <div class="section" id="import"> <span id="id10"></span><h3>Import<a class="headerlink" href="#import" title="Permalink to this headline">¶</a></h3> <p>Jinja2 supports putting often used code into macros. These macros can go into different templates and get imported from there. This works similar to the import statements in Python. It’s important to know that imports are cached and imported templates don’t have access to the current template variables, just the globals by default. For more details about context behavior of imports and includes see <a class="reference internal" href="#import-visibility"><em>Import Context Behavior</em></a>.</p> <p>There are two ways to import templates. You can import the complete template into a variable or request specific macros / exported variables from it.</p> <p>Imagine we have a helper module that renders forms (called <cite>forms.html</cite>):</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">macro</span> <span class="nv">input</span><span class="o">(</span><span class="nv">name</span><span class="o">,</span> <span class="nv">value</span><span class="o">=</span><span class="s1">''</span><span class="o">,</span> <span class="nv">type</span><span class="o">=</span><span class="s1">'text'</span><span class="o">)</span> -<span class="cp">%}</span> <span class="nt"><input</span> <span class="na">type=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">type</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">value=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">value</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">name=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span> <span class="cp">{%</span>- <span class="k">endmacro</span> <span class="cp">%}</span> <span class="cp">{%</span>- <span class="k">macro</span> <span class="nv">textarea</span><span class="o">(</span><span class="nv">name</span><span class="o">,</span> <span class="nv">value</span><span class="o">=</span><span class="s1">''</span><span class="o">,</span> <span class="nv">rows</span><span class="o">=</span><span class="m">10</span><span class="o">,</span> <span class="nv">cols</span><span class="o">=</span><span class="m">40</span><span class="o">)</span> -<span class="cp">%}</span> <span class="nt"><textarea</span> <span class="na">name=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">rows=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">rows</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">cols=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">cols</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">value</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></textarea></span> <span class="cp">{%</span>- <span class="k">endmacro</span> <span class="cp">%}</span> </pre></div> </div> <p>The easiest and most flexible is importing the whole module into a variable. That way you can access the attributes:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">import</span> <span class="s1">'forms.html'</span> <span class="k">as</span> <span class="nv">forms</span> <span class="cp">%}</span> <span class="nt"><dl></span> <span class="nt"><dt></span>Username<span class="nt"></dt></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">forms.input</span><span class="o">(</span><span class="s1">'username'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"><dt></span>Password<span class="nt"></dt></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">forms.input</span><span class="o">(</span><span class="s1">'password'</span><span class="o">,</span> <span class="nv">type</span><span class="o">=</span><span class="s1">'password'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"></dl></span> <span class="nt"><p></span><span class="cp">{{</span> <span class="nv">forms.textarea</span><span class="o">(</span><span class="s1">'comment'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></p></span> </pre></div> </div> <p>Alternatively you can import names from the template into the current namespace:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">from</span> <span class="s1">'forms.html'</span> <span class="k">import</span> <span class="nv">input</span> <span class="k">as</span> <span class="nv">input_field</span><span class="o">,</span> <span class="nv">textarea</span> <span class="cp">%}</span> <span class="nt"><dl></span> <span class="nt"><dt></span>Username<span class="nt"></dt></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">input_field</span><span class="o">(</span><span class="s1">'username'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"><dt></span>Password<span class="nt"></dt></span> <span class="nt"><dd></span><span class="cp">{{</span> <span class="nv">input_field</span><span class="o">(</span><span class="s1">'password'</span><span class="o">,</span> <span class="nv">type</span><span class="o">=</span><span class="s1">'password'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></dd></span> <span class="nt"></dl></span> <span class="nt"><p></span><span class="cp">{{</span> <span class="nv">textarea</span><span class="o">(</span><span class="s1">'comment'</span><span class="o">)</span> <span class="cp">}}</span><span class="nt"></p></span> </pre></div> </div> <p>Macros and variables starting with one or more underscores are private and cannot be imported.</p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.4: </span>If a template object was passed to the template context you can import from that object.</p> </div> </div> <div class="section" id="import-context-behavior"> <span id="import-visibility"></span><h2>Import Context Behavior<a class="headerlink" href="#import-context-behavior" title="Permalink to this headline">¶</a></h2> <p>Per default included templates are passed the current context and imported templates not. The reason for this is that imports unlike includes are cached as imports are often used just as a module that holds macros.</p> <p>This however can be changed of course explicitly. By adding <cite>with context</cite> or <cite>without context</cite> to the import/include directive the current context can be passed to the template and caching is disabled automatically.</p> <p>Here two examples:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">from</span> <span class="s1">'forms.html'</span> <span class="k">import</span> <span class="nv">input</span> <span class="k">with context</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">include</span> <span class="s1">'header.html'</span> <span class="k">without context</span> <span class="cp">%}</span> </pre></div> </div> <div class="admonition-note admonition"> <p class="first admonition-title">Note</p> <p>In Jinja 2.0 the context that was passed to the included template did not include variables defined in the template. As a matter of fact this did not work:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">box</span> <span class="k">in</span> <span class="nv">boxes</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">include</span> <span class="s2">"render_box.html"</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p class="last">The included template <tt class="docutils literal"><span class="pre">render_box.html</span></tt> is <em>not</em> able to access <cite>box</cite> in Jinja 2.0. As of Jinja 2.1 <tt class="docutils literal"><span class="pre">render_box.html</span></tt> <em>is</em> able to do so.</p> </div> </div> <div class="section" id="expressions"> <span id="id11"></span><h2>Expressions<a class="headerlink" href="#expressions" title="Permalink to this headline">¶</a></h2> <p>Jinja allows basic expressions everywhere. These work very similar to regular Python and even if you’re not working with Python you should feel comfortable with it.</p> <div class="section" id="literals"> <h3>Literals<a class="headerlink" href="#literals" title="Permalink to this headline">¶</a></h3> <p>The simplest form of expressions are literals. Literals are representations for Python objects such as strings and numbers. The following literals exist:</p> <dl class="docutils"> <dt>“Hello World”:</dt> <dd>Everything between two double or single quotes is a string. They are useful whenever you need a string in the template (for example as arguments to function calls, filters or just to extend or include a template).</dd> <dt>42 / 42.23:</dt> <dd>Integers and floating point numbers are created by just writing the number down. If a dot is present the number is a float, otherwise an integer. Keep in mind that for Python <tt class="docutils literal"><span class="pre">42</span></tt> and <tt class="docutils literal"><span class="pre">42.0</span></tt> is something different.</dd> <dt>[‘list’, ‘of’, ‘objects’]:</dt> <dd><p class="first">Everything between two brackets is a list. Lists are useful to store sequential data in or to iterate over them. For example you can easily create a list of links using lists and tuples with a for loop:</p> <div class="last highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">href</span><span class="o">,</span> <span class="nv">caption</span> <span class="k">in</span> <span class="o">[(</span><span class="s1">'index.html'</span><span class="o">,</span> <span class="s1">'Index'</span><span class="o">),</span> <span class="o">(</span><span class="s1">'about.html'</span><span class="o">,</span> <span class="s1">'About'</span><span class="o">),</span> <span class="o">(</span><span class="s1">'downloads.html'</span><span class="o">,</span> <span class="s1">'Downloads'</span><span class="o">)]</span> <span class="cp">%}</span> <span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">href</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">caption</span> <span class="cp">}}</span><span class="nt"></a></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> </dd> <dt>(‘tuple’, ‘of’, ‘values’):</dt> <dd>Tuples are like lists, just that you can’t modify them. If the tuple only has one item you have to end it with a comma. Tuples are usually used to represent items of two or more elements. See the example above for more details.</dd> <dt>{‘dict’: ‘of’, ‘key’: ‘and’, ‘value’: ‘pairs’}:</dt> <dd>A dict in Python is a structure that combines keys and values. Keys must be unique and always have exactly one value. Dicts are rarely used in templates, they are useful in some rare cases such as the <a class="reference internal" href="#xmlattr" title="xmlattr"><tt class="xref py py-func docutils literal"><span class="pre">xmlattr()</span></tt></a> filter.</dd> <dt>true / false:</dt> <dd>true is always true and false is always false.</dd> </dl> <div class="admonition-note admonition"> <p class="first admonition-title">Note</p> <p class="last">The special constants <cite>true</cite>, <cite>false</cite> and <cite>none</cite> are indeed lowercase. Because that caused confusion in the past, when writing <cite>True</cite> expands to an undefined variable that is considered false, all three of them can be written in title case too (<cite>True</cite>, <cite>False</cite>, and <cite>None</cite>). However for consistency (all Jinja identifiers are lowercase) you should use the lowercase versions.</p> </div> </div> <div class="section" id="math"> <h3>Math<a class="headerlink" href="#math" title="Permalink to this headline">¶</a></h3> <p>Jinja allows you to calculate with values. This is rarely useful in templates but exists for completeness’ sake. The following operators are supported:</p> <dl class="docutils"> <dt>+</dt> <dd>Adds two objects together. Usually the objects are numbers but if both are strings or lists you can concatenate them this way. This however is not the preferred way to concatenate strings! For string concatenation have a look at the <tt class="docutils literal"><span class="pre">~</span></tt> operator. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">1</span> <span class="pre">+</span> <span class="pre">1</span> <span class="pre">}}</span></tt> is <tt class="docutils literal"><span class="pre">2</span></tt>.</dd> <dt>-</dt> <dd>Substract the second number from the first one. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">3</span> <span class="pre">-</span> <span class="pre">2</span> <span class="pre">}}</span></tt> is <tt class="docutils literal"><span class="pre">1</span></tt>.</dd> </dl> <dl class="docutils"> <dt>/</dt> <dd>Divide two numbers. The return value will be a floating point number. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">1</span> <span class="pre">/</span> <span class="pre">2</span> <span class="pre">}}</span></tt> is <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">0.5</span> <span class="pre">}}</span></tt>.</dd> </dl> <dl class="docutils"> <dt>//</dt> <dd>Divide two numbers and return the truncated integer result. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">20</span> <span class="pre">//</span> <span class="pre">7</span> <span class="pre">}}</span></tt> is <tt class="docutils literal"><span class="pre">2</span></tt>.</dd> </dl> <dl class="docutils"> <dt>%</dt> <dd>Calculate the remainder of an integer division. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">11</span> <span class="pre">%</span> <span class="pre">7</span> <span class="pre">}}</span></tt> is <tt class="docutils literal"><span class="pre">4</span></tt>.</dd> <dt>*</dt> <dd>Multiply the left operand with the right one. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">2</span> <span class="pre">*</span> <span class="pre">2</span> <span class="pre">}}</span></tt> would return <tt class="docutils literal"><span class="pre">4</span></tt>. This can also be used to repeat a string multiple times. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">'='</span> <span class="pre">*</span> <span class="pre">80</span> <span class="pre">}}</span></tt> would print a bar of 80 equal signs.</dd> <dt>**</dt> <dd>Raise the left operand to the power of the right operand. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">2**3</span> <span class="pre">}}</span></tt> would return <tt class="docutils literal"><span class="pre">8</span></tt>.</dd> </dl> </div> <div class="section" id="comparisons"> <h3>Comparisons<a class="headerlink" href="#comparisons" title="Permalink to this headline">¶</a></h3> <dl class="docutils"> <dt>==</dt> <dd>Compares two objects for equality.</dd> <dt>!=</dt> <dd>Compares two objects for inequality.</dd> </dl> <dl class="docutils"> <dt>></dt> <dd><cite>true</cite> if the left hand side is greater than the right hand side.</dd> <dt>>=</dt> <dd><cite>true</cite> if the left hand side is greater or equal to the right hand side.</dd> </dl> <dl class="docutils"> <dt><</dt> <dd><cite>true</cite> if the left hand side is lower than the right hand side.</dd> <dt><=</dt> <dd><cite>true</cite> if the left hand side is lower or equal to the right hand side.</dd> </dl> </div> <div class="section" id="logic"> <h3>Logic<a class="headerlink" href="#logic" title="Permalink to this headline">¶</a></h3> <p>For <cite>if</cite> statements, <cite>for</cite> filtering or <cite>if</cite> expressions it can be useful to combine multiple expressions:</p> <dl class="docutils"> <dt>and</dt> <dd>Return true if the left and the right operand is true.</dd> <dt>or</dt> <dd>Return true if the left or the right operand is true.</dd> <dt>not</dt> <dd>negate a statement (see below).</dd> <dt>(expr)</dt> <dd>group an expression.</dd> </dl> <div class="admonition-note admonition"> <p class="first admonition-title">Note</p> <p class="last">The <tt class="docutils literal"><span class="pre">is</span></tt> and <tt class="docutils literal"><span class="pre">in</span></tt> operators support negation using an infix notation too: <tt class="docutils literal"><span class="pre">foo</span> <span class="pre">is</span> <span class="pre">not</span> <span class="pre">bar</span></tt> and <tt class="docutils literal"><span class="pre">foo</span> <span class="pre">not</span> <span class="pre">in</span> <span class="pre">bar</span></tt> instead of <tt class="docutils literal"><span class="pre">not</span> <span class="pre">foo</span> <span class="pre">is</span> <span class="pre">bar</span></tt> and <tt class="docutils literal"><span class="pre">not</span> <span class="pre">foo</span> <span class="pre">in</span> <span class="pre">bar</span></tt>. All other expressions require a prefix notation: <tt class="docutils literal"><span class="pre">not</span> <span class="pre">(foo</span> <span class="pre">and</span> <span class="pre">bar).</span></tt></p> </div> </div> <div class="section" id="other-operators"> <h3>Other Operators<a class="headerlink" href="#other-operators" title="Permalink to this headline">¶</a></h3> <p>The following operators are very useful but don’t fit into any of the other two categories:</p> <dl class="docutils"> <dt>in</dt> <dd>Perform sequence / mapping containment test. Returns true if the left operand is contained in the right. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">1</span> <span class="pre">in</span> <span class="pre">[1,</span> <span class="pre">2,</span> <span class="pre">3]</span> <span class="pre">}}</span></tt> would for example return true.</dd> <dt>is</dt> <dd>Performs a <a class="reference internal" href="#tests"><em>test</em></a>.</dd> <dt>|</dt> <dd>Applies a <a class="reference internal" href="#filters"><em>filter</em></a>.</dd> </dl> <dl class="docutils"> <dt>~</dt> <dd>Converts all operands into strings and concatenates them. <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">"Hello</span> <span class="pre">"</span> <span class="pre">~</span> <span class="pre">name</span> <span class="pre">~</span> <span class="pre">"!"</span> <span class="pre">}}</span></tt> would return (assuming <cite>name</cite> is <tt class="docutils literal"><span class="pre">'John'</span></tt>) <tt class="docutils literal"><span class="pre">Hello</span> <span class="pre">John!</span></tt>.</dd> <dt>()</dt> <dd>Call a callable: <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">post.render()</span> <span class="pre">}}</span></tt>. Inside of the parentheses you can use positional arguments and keyword arguments like in python: <tt class="docutils literal"><span class="pre">{{</span> <span class="pre">post.render(user,</span> <span class="pre">full=true)</span> <span class="pre">}}</span></tt>.</dd> <dt>. / []</dt> <dd>Get an attribute of an object. (See <a class="reference internal" href="#variables"><em>Variables</em></a>)</dd> </dl> </div> <div class="section" id="if-expression"> <span id="id12"></span><h3>If Expression<a class="headerlink" href="#if-expression" title="Permalink to this headline">¶</a></h3> <p>It is also possible to use inline <cite>if</cite> expressions. These are useful in some situations. For example you can use this to extend from one template if a variable is defined, otherwise from the default layout template:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">extends</span> <span class="nv">layout_template</span> <span class="k">if</span> <span class="nv">layout_template</span> <span class="k">is</span> <span class="nf">defined</span> <span class="k">else</span> <span class="s1">'master.html'</span> <span class="cp">%}</span> </pre></div> </div> <p>The general syntax is <tt class="docutils literal"><span class="pre"><do</span> <span class="pre">something></span> <span class="pre">if</span> <span class="pre"><something</span> <span class="pre">is</span> <span class="pre">true></span> <span class="pre">else</span> <span class="pre"><do</span> <span class="pre">something</span> <span class="pre">else></span></tt>.</p> <p>The <cite>else</cite> part is optional. If not provided the else block implicitly evaluates into an undefined object:</p> <div class="highlight-html+jinja"><pre>{{ '[%s]' % page.title if page.title }}</pre> </div> </div> </div> <div class="section" id="list-of-builtin-filters"> <span id="builtin-filters"></span><h2>List of Builtin Filters<a class="headerlink" href="#list-of-builtin-filters" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="abs"> <tt class="descname">abs</tt><big>(</big><em>number</em><big>)</big><a class="headerlink" href="#abs" title="Permalink to this definition">¶</a></dt> <dd><p>Return the absolute value of the argument.</p> </dd></dl> <dl class="function"> <dt id="attr"> <tt class="descname">attr</tt><big>(</big><em>obj</em>, <em>name</em><big>)</big><a class="headerlink" href="#attr" title="Permalink to this definition">¶</a></dt> <dd><p>Get an attribute of an object. <tt class="docutils literal"><span class="pre">foo|attr("bar")</span></tt> works like <tt class="docutils literal"><span class="pre">foo["bar"]</span></tt> just that always an attribute is returned and items are not looked up.</p> <p>See <a class="reference internal" href="#notes-on-subscriptions"><em>Notes on subscriptions</em></a> for more details.</p> </dd></dl> <dl class="function"> <dt id="batch"> <tt class="descname">batch</tt><big>(</big><em>value</em>, <em>linecount</em>, <em>fill_with=None</em><big>)</big><a class="headerlink" href="#batch" title="Permalink to this definition">¶</a></dt> <dd><p>A filter that batches items. It works pretty much like <cite>slice</cite> just the other way round. It returns a list of lists with the given number of items. If you provide a second parameter this is used to fill up missing items. See this example:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><table></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">row</span> <span class="k">in</span> <span class="nv">items</span><span class="o">|</span><span class="nf">batch</span><span class="o">(</span><span class="m">3</span><span class="o">,</span> <span class="s1">'&nbsp;'</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><tr></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">column</span> <span class="k">in</span> <span class="nv">row</span> <span class="cp">%}</span> <span class="nt"><td></span><span class="cp">{{</span> <span class="nv">column</span> <span class="cp">}}</span><span class="nt"></td></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></tr></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></table></span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="capitalize"> <tt class="descname">capitalize</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#capitalize" title="Permalink to this definition">¶</a></dt> <dd><p>Capitalize a value. The first character will be uppercase, all others lowercase.</p> </dd></dl> <dl class="function"> <dt id="center"> <tt class="descname">center</tt><big>(</big><em>value</em>, <em>width=80</em><big>)</big><a class="headerlink" href="#center" title="Permalink to this definition">¶</a></dt> <dd><p>Centers the value in a field of a given width.</p> </dd></dl> <dl class="function"> <dt id="default"> <tt class="descname">default</tt><big>(</big><em>value</em>, <em>default_value=u''</em>, <em>boolean=False</em><big>)</big><a class="headerlink" href="#default" title="Permalink to this definition">¶</a></dt> <dd><p>If the value is undefined it will return the passed default value, otherwise the value of the variable:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">my_variable</span><span class="o">|</span><span class="nf">default</span><span class="o">(</span><span class="s1">'my_variable is not defined'</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p>This will output the value of <tt class="docutils literal"><span class="pre">my_variable</span></tt> if the variable was defined, otherwise <tt class="docutils literal"><span class="pre">'my_variable</span> <span class="pre">is</span> <span class="pre">not</span> <span class="pre">defined'</span></tt>. If you want to use default with variables that evaluate to false you have to set the second parameter to <cite>true</cite>:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="s1">''</span><span class="o">|</span><span class="nf">default</span><span class="o">(</span><span class="s1">'the string was empty'</span><span class="o">,</span> <span class="kp">true</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Aliases :</th><td class="field-body"><tt class="docutils literal"><span class="pre">d</span></tt></td> </tr> </tbody> </table> </dd></dl> <dl class="function"> <dt id="dictsort"> <tt class="descname">dictsort</tt><big>(</big><em>value</em>, <em>case_sensitive=False</em>, <em>by='key'</em><big>)</big><a class="headerlink" href="#dictsort" title="Permalink to this definition">¶</a></dt> <dd><p>Sort a dict and yield (key, value) pairs. Because python dicts are unsorted you may want to use this function to order them by either key or value:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">mydict</span><span class="o">|</span><span class="nf">dictsort</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> sort the dict by key, case insensitive</span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">mydict</span><span class="o">|</span><span class="nf">dictsort</span><span class="o">(</span><span class="kp">true</span><span class="o">)</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> sort the dict by key, case sensitive</span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">mydict</span><span class="o">|</span><span class="nf">dictsort</span><span class="o">(</span><span class="kp">false</span><span class="o">,</span> <span class="s1">'value'</span><span class="o">)</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> sort the dict by key, case insensitive, sorted</span> <span class="x"> normally and ordered by value.</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="escape"> <tt class="descname">escape</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#escape" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the characters &, <, >, ‘, and ” in string s to HTML-safe sequences. Use this if you need to display text that might contain such characters in HTML. Marks return value as markup string.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Aliases :</th><td class="field-body"><tt class="docutils literal"><span class="pre">e</span></tt></td> </tr> </tbody> </table> </dd></dl> <dl class="function"> <dt id="filesizeformat"> <tt class="descname">filesizeformat</tt><big>(</big><em>value</em>, <em>binary=False</em><big>)</big><a class="headerlink" href="#filesizeformat" title="Permalink to this definition">¶</a></dt> <dd><p>Format the value like a ‘human-readable’ file size (i.e. 13 kB, 4.1 MB, 102 Bytes, etc). Per default decimal prefixes are used (Mega, Giga, etc.), if the second parameter is set to <cite>True</cite> the binary prefixes are used (Mebi, Gibi).</p> </dd></dl> <dl class="function"> <dt id="first"> <tt class="descname">first</tt><big>(</big><em>seq</em><big>)</big><a class="headerlink" href="#first" title="Permalink to this definition">¶</a></dt> <dd><p>Return the first item of a sequence.</p> </dd></dl> <dl class="function"> <dt id="float"> <tt class="descname">float</tt><big>(</big><em>value</em>, <em>default=0.0</em><big>)</big><a class="headerlink" href="#float" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the value into a floating point number. If the conversion doesn’t work it will return <tt class="docutils literal"><span class="pre">0.0</span></tt>. You can override this default using the first parameter.</p> </dd></dl> <dl class="function"> <dt id="forceescape"> <tt class="descname">forceescape</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#forceescape" title="Permalink to this definition">¶</a></dt> <dd><p>Enforce HTML escaping. This will probably double escape variables.</p> </dd></dl> <dl class="function"> <dt id="format"> <tt class="descname">format</tt><big>(</big><em>value</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#format" title="Permalink to this definition">¶</a></dt> <dd><p>Apply python string formatting on an object:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="s2">"%s - %s"</span><span class="o">|</span><span class="nf">format</span><span class="o">(</span><span class="s2">"Hello?"</span><span class="o">,</span> <span class="s2">"Foo!"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> Hello? - Foo!</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="groupby"> <tt class="descname">groupby</tt><big>(</big><em>value</em>, <em>attribute</em><big>)</big><a class="headerlink" href="#groupby" title="Permalink to this definition">¶</a></dt> <dd><p>Group a sequence of objects by a common attribute.</p> <p>If you for example have a list of dicts or objects that represent persons with <cite>gender</cite>, <cite>first_name</cite> and <cite>last_name</cite> attributes and you want to group all users by genders you can do something like the following snippet:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">group</span> <span class="k">in</span> <span class="nv">persons</span><span class="o">|</span><span class="nf">groupby</span><span class="o">(</span><span class="s1">'gender'</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">group.grouper</span> <span class="cp">}}</span><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">person</span> <span class="k">in</span> <span class="nv">group.list</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">person.first_name</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">person.last_name</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span><span class="nt"></ul></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>Additionally it’s possible to use tuple unpacking for the grouper and list:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">grouper</span><span class="o">,</span> <span class="nv">list</span> <span class="k">in</span> <span class="nv">persons</span><span class="o">|</span><span class="nf">groupby</span><span class="o">(</span><span class="s1">'gender'</span><span class="o">)</span> <span class="cp">%}</span> ... <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>As you can see the item we’re grouping by is stored in the <cite>grouper</cite> attribute and the <cite>list</cite> contains all the objects that have this grouper in common.</p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.6: </span>It’s now possible to use dotted notation to group by the child attribute of another attribute.</p> </dd></dl> <dl class="function"> <dt id="indent"> <tt class="descname">indent</tt><big>(</big><em>s</em>, <em>width=4</em>, <em>indentfirst=False</em><big>)</big><a class="headerlink" href="#indent" title="Permalink to this definition">¶</a></dt> <dd><p>Return a copy of the passed string, each line indented by 4 spaces. The first line is not indented. If you want to change the number of spaces or indent the first line too you can pass additional parameters to the filter:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">mytext</span><span class="o">|</span><span class="nf">indent</span><span class="o">(</span><span class="m">2</span><span class="o">,</span> <span class="kp">true</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> indent by two spaces and indent the first line too.</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="int"> <tt class="descname">int</tt><big>(</big><em>value</em>, <em>default=0</em><big>)</big><a class="headerlink" href="#int" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the value into an integer. If the conversion doesn’t work it will return <tt class="docutils literal"><span class="pre">0</span></tt>. You can override this default using the first parameter.</p> </dd></dl> <dl class="function"> <dt id="join"> <tt class="descname">join</tt><big>(</big><em>value</em>, <em>d=u''</em>, <em>attribute=None</em><big>)</big><a class="headerlink" href="#join" title="Permalink to this definition">¶</a></dt> <dd><p>Return a string which is the concatenation of the strings in the sequence. The separator between elements is an empty string per default, you can define it with the optional parameter:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="o">[</span><span class="m">1</span><span class="o">,</span> <span class="m">2</span><span class="o">,</span> <span class="m">3</span><span class="o">]|</span><span class="nf">join</span><span class="o">(</span><span class="s1">'|'</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> 1|2|3</span> <span class="cp">{{</span> <span class="o">[</span><span class="m">1</span><span class="o">,</span> <span class="m">2</span><span class="o">,</span> <span class="m">3</span><span class="o">]|</span><span class="nf">join</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> 123</span> </pre></div> </div> <p>It is also possible to join certain attributes of an object:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">join</span><span class="o">(</span><span class="s1">', '</span><span class="o">,</span> <span class="nv">attribute</span><span class="o">=</span><span class="s1">'username'</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.6: </span>The <cite>attribute</cite> parameter was added.</p> </dd></dl> <dl class="function"> <dt id="last"> <tt class="descname">last</tt><big>(</big><em>seq</em><big>)</big><a class="headerlink" href="#last" title="Permalink to this definition">¶</a></dt> <dd><p>Return the last item of a sequence.</p> </dd></dl> <dl class="function"> <dt id="length"> <tt class="descname">length</tt><big>(</big><em>object</em><big>)</big><a class="headerlink" href="#length" title="Permalink to this definition">¶</a></dt> <dd><p>Return the number of items of a sequence or mapping.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Aliases :</th><td class="field-body"><tt class="docutils literal"><span class="pre">count</span></tt></td> </tr> </tbody> </table> </dd></dl> <dl class="function"> <dt id="list"> <tt class="descname">list</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#list" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the value into a list. If it was a string the returned list will be a list of characters.</p> </dd></dl> <dl class="function"> <dt id="lower"> <tt class="descname">lower</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#lower" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a value to lowercase.</p> </dd></dl> <dl class="function"> <dt id="map"> <tt class="descname">map</tt><big>(</big><big>)</big><a class="headerlink" href="#map" title="Permalink to this definition">¶</a></dt> <dd><p>Applies a filter on a sequence of objects or looks up an attribute. This is useful when dealing with lists of objects but you are really only interested in a certain value of it.</p> <p>The basic usage is mapping on an attribute. Imagine you have a list of users but you are only interested in a list of usernames:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="x">Users on this page: </span><span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">map</span><span class="o">(</span><span class="nv">attribute</span><span class="o">=</span><span class="s1">'username'</span><span class="o">)|</span><span class="nf">join</span><span class="o">(</span><span class="s1">', '</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p>Alternatively you can let it invoke a filter by passing the name of the filter and the arguments afterwards. A good example would be applying a text conversion filter on a sequence:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="x">Users on this page: </span><span class="cp">{{</span> <span class="nv">titles</span><span class="o">|</span><span class="nf">map</span><span class="o">(</span><span class="s1">'lower'</span><span class="o">)|</span><span class="nf">join</span><span class="o">(</span><span class="s1">', '</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="pprint"> <tt class="descname">pprint</tt><big>(</big><em>value</em>, <em>verbose=False</em><big>)</big><a class="headerlink" href="#pprint" title="Permalink to this definition">¶</a></dt> <dd><p>Pretty print a variable. Useful for debugging.</p> <p>With Jinja 1.2 onwards you can pass it a parameter. If this parameter is truthy the output will be more verbose (this requires <cite>pretty</cite>)</p> </dd></dl> <dl class="function"> <dt id="random"> <tt class="descname">random</tt><big>(</big><em>seq</em><big>)</big><a class="headerlink" href="#random" title="Permalink to this definition">¶</a></dt> <dd><p>Return a random item from the sequence.</p> </dd></dl> <dl class="function"> <dt id="reject"> <tt class="descname">reject</tt><big>(</big><big>)</big><a class="headerlink" href="#reject" title="Permalink to this definition">¶</a></dt> <dd><p>Filters a sequence of objects by appying a test to either the object or the attribute and rejecting the ones with the test succeeding.</p> <p>Example usage:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">numbers</span><span class="o">|</span><span class="nf">reject</span><span class="o">(</span><span class="s2">"odd"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="rejectattr"> <tt class="descname">rejectattr</tt><big>(</big><big>)</big><a class="headerlink" href="#rejectattr" title="Permalink to this definition">¶</a></dt> <dd><p>Filters a sequence of objects by appying a test to either the object or the attribute and rejecting the ones with the test succeeding.</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">rejectattr</span><span class="o">(</span><span class="s2">"is_active"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">rejectattr</span><span class="o">(</span><span class="s2">"email"</span><span class="o">,</span> <span class="s2">"none"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="replace"> <tt class="descname">replace</tt><big>(</big><em>s</em>, <em>old</em>, <em>new</em>, <em>count=None</em><big>)</big><a class="headerlink" href="#replace" title="Permalink to this definition">¶</a></dt> <dd><p>Return a copy of the value with all occurrences of a substring replaced with a new one. The first argument is the substring that should be replaced, the second is the replacement string. If the optional third argument <tt class="docutils literal"><span class="pre">count</span></tt> is given, only the first <tt class="docutils literal"><span class="pre">count</span></tt> occurrences are replaced:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="s2">"Hello World"</span><span class="o">|</span><span class="nf">replace</span><span class="o">(</span><span class="s2">"Hello"</span><span class="o">,</span> <span class="s2">"Goodbye"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> Goodbye World</span> <span class="cp">{{</span> <span class="s2">"aaaaargh"</span><span class="o">|</span><span class="nf">replace</span><span class="o">(</span><span class="s2">"a"</span><span class="o">,</span> <span class="s2">"d'oh, "</span><span class="o">,</span> <span class="m">2</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> d'oh, d'oh, aaargh</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="reverse"> <tt class="descname">reverse</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#reverse" title="Permalink to this definition">¶</a></dt> <dd><p>Reverse the object or return an iterator the iterates over it the other way round.</p> </dd></dl> <dl class="function"> <dt id="round"> <tt class="descname">round</tt><big>(</big><em>value</em>, <em>precision=0</em>, <em>method='common'</em><big>)</big><a class="headerlink" href="#round" title="Permalink to this definition">¶</a></dt> <dd><p>Round the number to a given precision. The first parameter specifies the precision (default is <tt class="docutils literal"><span class="pre">0</span></tt>), the second the rounding method:</p> <ul class="simple"> <li><tt class="docutils literal"><span class="pre">'common'</span></tt> rounds either up or down</li> <li><tt class="docutils literal"><span class="pre">'ceil'</span></tt> always rounds up</li> <li><tt class="docutils literal"><span class="pre">'floor'</span></tt> always rounds down</li> </ul> <p>If you don’t specify a method <tt class="docutils literal"><span class="pre">'common'</span></tt> is used.</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="m">42.55</span><span class="o">|</span><span class="nf">round</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> 43.0</span> <span class="cp">{{</span> <span class="m">42.55</span><span class="o">|</span><span class="nf">round</span><span class="o">(</span><span class="m">1</span><span class="o">,</span> <span class="s1">'floor'</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> 42.5</span> </pre></div> </div> <p>Note that even if rounded to 0 precision, a float is returned. If you need a real integer, pipe it through <cite>int</cite>:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="m">42.55</span><span class="o">|</span><span class="nf">round</span><span class="o">|</span><span class="nf">int</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> 43</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="safe"> <tt class="descname">safe</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#safe" title="Permalink to this definition">¶</a></dt> <dd><p>Mark the value as safe which means that in an environment with automatic escaping enabled this variable will not be escaped.</p> </dd></dl> <dl class="function"> <dt id="select"> <tt class="descname">select</tt><big>(</big><big>)</big><a class="headerlink" href="#select" title="Permalink to this definition">¶</a></dt> <dd><p>Filters a sequence of objects by appying a test to either the object or the attribute and only selecting the ones with the test succeeding.</p> <p>Example usage:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">numbers</span><span class="o">|</span><span class="nf">select</span><span class="o">(</span><span class="s2">"odd"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="selectattr"> <tt class="descname">selectattr</tt><big>(</big><big>)</big><a class="headerlink" href="#selectattr" title="Permalink to this definition">¶</a></dt> <dd><p>Filters a sequence of objects by appying a test to either the object or the attribute and only selecting the ones with the test succeeding.</p> <p>Example usage:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">selectattr</span><span class="o">(</span><span class="s2">"is_active"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="cp">{{</span> <span class="nv">users</span><span class="o">|</span><span class="nf">selectattr</span><span class="o">(</span><span class="s2">"email"</span><span class="o">,</span> <span class="s2">"none"</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="slice"> <tt class="descname">slice</tt><big>(</big><em>value</em>, <em>slices</em>, <em>fill_with=None</em><big>)</big><a class="headerlink" href="#slice" title="Permalink to this definition">¶</a></dt> <dd><p>Slice an iterator and return a list of lists containing those items. Useful if you want to create a div containing three ul tags that represent columns:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><div</span> <span class="na">class=</span><span class="s">"columwrapper"</span><span class="nt">></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">column</span> <span class="k">in</span> <span class="nv">items</span><span class="o">|</span><span class="nf">slice</span><span class="o">(</span><span class="m">3</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><ul</span> <span class="na">class=</span><span class="s">"column-</span><span class="cp">{{</span> <span class="nb">loop</span><span class="nv">.index</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span> <span class="cp">{%</span>- <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">column</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">item</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></div></span> </pre></div> </div> <p>If you pass it a second argument it’s used to fill missing values on the last iteration.</p> </dd></dl> <dl class="function"> <dt id="sort"> <tt class="descname">sort</tt><big>(</big><em>value</em>, <em>reverse=False</em>, <em>case_sensitive=False</em>, <em>attribute=None</em><big>)</big><a class="headerlink" href="#sort" title="Permalink to this definition">¶</a></dt> <dd><p>Sort an iterable. Per default it sorts ascending, if you pass it true as first argument it will reverse the sorting.</p> <p>If the iterable is made of strings the third parameter can be used to control the case sensitiveness of the comparison which is disabled by default.</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">iterable</span><span class="o">|</span><span class="nf">sort</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> ...</span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span><span class="x"></span> </pre></div> </div> <p>It is also possible to sort by an attribute (for example to sort by the date of an object) by specifying the <cite>attribute</cite> parameter:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">item</span> <span class="k">in</span> <span class="nv">iterable</span><span class="o">|</span><span class="nf">sort</span><span class="o">(</span><span class="nv">attribute</span><span class="o">=</span><span class="s1">'date'</span><span class="o">)</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> ...</span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span><span class="x"></span> </pre></div> </div> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.6: </span>The <cite>attribute</cite> parameter was added.</p> </dd></dl> <dl class="function"> <dt id="string"> <tt class="descname">string</tt><big>(</big><em>object</em><big>)</big><a class="headerlink" href="#string" title="Permalink to this definition">¶</a></dt> <dd><p>Make a string unicode if it isn’t already. That way a markup string is not converted back to unicode.</p> </dd></dl> <dl class="function"> <dt id="striptags"> <tt class="descname">striptags</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#striptags" title="Permalink to this definition">¶</a></dt> <dd><p>Strip SGML/XML tags and replace adjacent whitespace by one space.</p> </dd></dl> <dl class="function"> <dt id="sum"> <tt class="descname">sum</tt><big>(</big><em>iterable</em>, <em>attribute=None</em>, <em>start=0</em><big>)</big><a class="headerlink" href="#sum" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the sum of a sequence of numbers plus the value of parameter ‘start’ (which defaults to 0). When the sequence is empty it returns start.</p> <p>It is also possible to sum up only certain attributes:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="x">Total: </span><span class="cp">{{</span> <span class="nv">items</span><span class="o">|</span><span class="nf">sum</span><span class="o">(</span><span class="nv">attribute</span><span class="o">=</span><span class="s1">'price'</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> </pre></div> </div> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.6: </span>The <cite>attribute</cite> parameter was added to allow suming up over attributes. Also the <cite>start</cite> parameter was moved on to the right.</p> </dd></dl> <dl class="function"> <dt id="title"> <tt class="descname">title</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#title" title="Permalink to this definition">¶</a></dt> <dd><p>Return a titlecased version of the value. I.e. words will start with uppercase letters, all remaining characters are lowercase.</p> </dd></dl> <dl class="function"> <dt id="trim"> <tt class="descname">trim</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#trim" title="Permalink to this definition">¶</a></dt> <dd><p>Strip leading and trailing whitespace.</p> </dd></dl> <dl class="function"> <dt id="truncate"> <tt class="descname">truncate</tt><big>(</big><em>s</em>, <em>length=255</em>, <em>killwords=False</em>, <em>end='...'</em><big>)</big><a class="headerlink" href="#truncate" title="Permalink to this definition">¶</a></dt> <dd><p>Return a truncated copy of the string. The length is specified with the first parameter which defaults to <tt class="docutils literal"><span class="pre">255</span></tt>. If the second parameter is <tt class="docutils literal"><span class="pre">true</span></tt> the filter will cut the text at length. Otherwise it will discard the last word. If the text was in fact truncated it will append an ellipsis sign (<tt class="docutils literal"><span class="pre">"..."</span></tt>). If you want a different ellipsis sign than <tt class="docutils literal"><span class="pre">"..."</span></tt> you can specify it using the third parameter.</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="s2">"foo bar"</span><span class="o">|</span><span class="nf">truncate</span><span class="o">(</span><span class="m">5</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> "foo ..."</span> <span class="cp">{{</span> <span class="s2">"foo bar"</span><span class="o">|</span><span class="nf">truncate</span><span class="o">(</span><span class="m">5</span><span class="o">,</span> <span class="kp">True</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> -> "foo b..."</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="upper"> <tt class="descname">upper</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#upper" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a value to uppercase.</p> </dd></dl> <dl class="function"> <dt id="urlencode"> <tt class="descname">urlencode</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#urlencode" title="Permalink to this definition">¶</a></dt> <dd><p>Escape strings for use in URLs (uses UTF-8 encoding). It accepts both dictionaries and regular strings as well as pairwise iterables.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.7.</span></p> </dd></dl> <dl class="function"> <dt id="urlize"> <tt class="descname">urlize</tt><big>(</big><em>value</em>, <em>trim_url_limit=None</em>, <em>nofollow=False</em><big>)</big><a class="headerlink" href="#urlize" title="Permalink to this definition">¶</a></dt> <dd><p>Converts URLs in plain text into clickable links.</p> <p>If you pass the filter an additional integer it will shorten the urls to that number. Also a third argument exists that makes the urls “nofollow”:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">mytext</span><span class="o">|</span><span class="nf">urlize</span><span class="o">(</span><span class="m">40</span><span class="o">,</span> <span class="kp">true</span><span class="o">)</span> <span class="cp">}}</span><span class="x"></span> <span class="x"> links are shortened to 40 chars and defined with rel="nofollow"</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="wordcount"> <tt class="descname">wordcount</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#wordcount" title="Permalink to this definition">¶</a></dt> <dd><p>Count the words in that string.</p> </dd></dl> <dl class="function"> <dt id="wordwrap"> <tt class="descname">wordwrap</tt><big>(</big><em>s</em>, <em>width=79</em>, <em>break_long_words=True</em>, <em>wrapstring=None</em><big>)</big><a class="headerlink" href="#wordwrap" title="Permalink to this definition">¶</a></dt> <dd><p>Return a copy of the string passed to the filter wrapped after <tt class="docutils literal"><span class="pre">79</span></tt> characters. You can override this default using the first parameter. If you set the second parameter to <cite>false</cite> Jinja will not split words apart if they are longer than <cite>width</cite>. By default, the newlines will be the default newlines for the environment, but this can be changed using the wrapstring keyword argument.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.7: </span>Added support for the <cite>wrapstring</cite> parameter.</p> </dd></dl> <dl class="function"> <dt id="xmlattr"> <tt class="descname">xmlattr</tt><big>(</big><em>d</em>, <em>autospace=True</em><big>)</big><a class="headerlink" href="#xmlattr" title="Permalink to this definition">¶</a></dt> <dd><p>Create an SGML/XML attribute string based on the items in a dict. All values that are neither <cite>none</cite> nor <cite>undefined</cite> are automatically escaped:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul</span><span class="cp">{{</span> <span class="o">{</span><span class="s1">'class'</span><span class="o">:</span> <span class="s1">'my_list'</span><span class="o">,</span> <span class="s1">'missing'</span><span class="o">:</span> <span class="kp">none</span><span class="o">,</span> <span class="s1">'id'</span><span class="o">:</span> <span class="s1">'list-%d'</span><span class="o">|</span><span class="nf">format</span><span class="o">(</span><span class="nv">variable</span><span class="o">)}|</span><span class="nf">xmlattr</span> <span class="cp">}}</span><span class="nt">></span> ... <span class="nt"></ul></span> </pre></div> </div> <p>Results in something like this:</p> <div class="highlight-html"><div class="highlight"><pre><span class="nt"><ul</span> <span class="na">class=</span><span class="s">"my_list"</span> <span class="na">id=</span><span class="s">"list-42"</span><span class="nt">></span> ... <span class="nt"></ul></span> </pre></div> </div> <p>As you can see it automatically prepends a space in front of the item if the filter returned something unless the second parameter is false.</p> </dd></dl> </div> <div class="section" id="list-of-builtin-tests"> <span id="builtin-tests"></span><h2>List of Builtin Tests<a class="headerlink" href="#list-of-builtin-tests" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="callable"> <tt class="descname">callable</tt><big>(</big><em>object</em><big>)</big><a class="headerlink" href="#callable" title="Permalink to this definition">¶</a></dt> <dd><p>Return whether the object is callable (i.e., some kind of function). Note that classes are callable, as are instances with a __call__() method.</p> </dd></dl> <dl class="function"> <dt id="defined"> <tt class="descname">defined</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#defined" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is defined:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">if</span> <span class="nv">variable</span> <span class="k">is</span> <span class="nf">defined</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> value of variable: </span><span class="cp">{{</span> <span class="nv">variable</span> <span class="cp">}}</span><span class="x"></span> <span class="cp">{%</span> <span class="k">else</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> variable is not defined</span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span><span class="x"></span> </pre></div> </div> <p>See the <a class="reference internal" href="#default" title="default"><tt class="xref py py-func docutils literal"><span class="pre">default()</span></tt></a> filter for a simple way to set undefined variables.</p> </dd></dl> <dl class="function"> <dt id="divisibleby"> <tt class="descname">divisibleby</tt><big>(</big><em>value</em>, <em>num</em><big>)</big><a class="headerlink" href="#divisibleby" title="Permalink to this definition">¶</a></dt> <dd><p>Check if a variable is divisible by a number.</p> </dd></dl> <dl class="function"> <dt id="escaped"> <tt class="descname">escaped</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#escaped" title="Permalink to this definition">¶</a></dt> <dd><p>Check if the value is escaped.</p> </dd></dl> <dl class="function"> <dt id="even"> <tt class="descname">even</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#even" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is even.</p> </dd></dl> <dl class="function"> <dt id="iterable"> <tt class="descname">iterable</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#iterable" title="Permalink to this definition">¶</a></dt> <dd><p>Check if it’s possible to iterate over an object.</p> </dd></dl> <dl class="function"> <dt> <tt class="descname">lower</tt><big>(</big><em>value</em><big>)</big></dt> <dd><p>Return true if the variable is lowercased.</p> </dd></dl> <dl class="function"> <dt id="mapping"> <tt class="descname">mapping</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#mapping" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the object is a mapping (dict etc.).</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="function"> <dt id="none"> <tt class="descname">none</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#none" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is none.</p> </dd></dl> <dl class="function"> <dt id="number"> <tt class="descname">number</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#number" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is a number.</p> </dd></dl> <dl class="function"> <dt id="odd"> <tt class="descname">odd</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#odd" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is odd.</p> </dd></dl> <dl class="function"> <dt id="sameas"> <tt class="descname">sameas</tt><big>(</big><em>value</em>, <em>other</em><big>)</big><a class="headerlink" href="#sameas" title="Permalink to this definition">¶</a></dt> <dd><p>Check if an object points to the same memory address than another object:</p> <div class="highlight-jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">if</span> <span class="nv">foo.attribute</span> <span class="k">is</span> <span class="nf">sameas</span> <span class="kp">false</span> <span class="cp">%}</span><span class="x"></span> <span class="x"> the foo attribute really is the `False` singleton</span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span><span class="x"></span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="sequence"> <tt class="descname">sequence</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#sequence" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if the variable is a sequence. Sequences are variables that are iterable.</p> </dd></dl> <dl class="function"> <dt> <tt class="descname">string</tt><big>(</big><em>value</em><big>)</big></dt> <dd><p>Return true if the object is a string.</p> </dd></dl> <dl class="function"> <dt id="undefined"> <tt class="descname">undefined</tt><big>(</big><em>value</em><big>)</big><a class="headerlink" href="#undefined" title="Permalink to this definition">¶</a></dt> <dd><p>Like <a class="reference internal" href="#defined" title="defined"><tt class="xref py py-func docutils literal"><span class="pre">defined()</span></tt></a> but the other way round.</p> </dd></dl> <dl class="function"> <dt> <tt class="descname">upper</tt><big>(</big><em>value</em><big>)</big></dt> <dd><p>Return true if the variable is uppercased.</p> </dd></dl> </div> <div class="section" id="list-of-global-functions"> <span id="builtin-globals"></span><h2>List of Global Functions<a class="headerlink" href="#list-of-global-functions" title="Permalink to this headline">¶</a></h2> <p>The following functions are available in the global scope by default:</p> <dl class="function"> <dt id="range"> <tt class="descname">range</tt><big>(</big><span class="optional">[</span><em>start</em><span class="optional">]</span>, <em>stop</em><span class="optional">[</span>, <em>step</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#range" title="Permalink to this definition">¶</a></dt> <dd><p>Return a list containing an arithmetic progression of integers. range(i, j) returns [i, i+1, i+2, ..., j-1]; start (!) defaults to 0. When step is given, it specifies the increment (or decrement). For example, range(4) returns [0, 1, 2, 3]. The end point is omitted! These are exactly the valid indices for a list of 4 elements.</p> <p>This is useful to repeat a template block multiple times for example to fill a list. Imagine you have 7 users in the list but you want to render three empty items to enforce a height with CSS:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><ul></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="nt"><li></span><span class="cp">{{</span> <span class="nv">user.username</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">number</span> <span class="k">in</span> <span class="nv">range</span><span class="o">(</span><span class="m">10</span> <span class="o">-</span> <span class="nv">users</span><span class="o">|</span><span class="nf">count</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><li</span> <span class="na">class=</span><span class="s">"empty"</span><span class="nt">><span></span>...<span class="nt"></span></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="lipsum"> <tt class="descname">lipsum</tt><big>(</big><em>n=5</em>, <em>html=True</em>, <em>min=20</em>, <em>max=100</em><big>)</big><a class="headerlink" href="#lipsum" title="Permalink to this definition">¶</a></dt> <dd><p>Generates some lorem ipsum for the template. Per default five paragraphs with HTML are generated each paragraph between 20 and 100 words. If html is disabled regular text is returned. This is useful to generate simple contents for layout testing.</p> </dd></dl> <dl class="function"> <dt id="dict"> <tt class="descname">dict</tt><big>(</big><em>**items</em><big>)</big><a class="headerlink" href="#dict" title="Permalink to this definition">¶</a></dt> <dd><p>A convenient alternative to dict literals. <tt class="docutils literal"><span class="pre">{'foo':</span> <span class="pre">'bar'}</span></tt> is the same as <tt class="docutils literal"><span class="pre">dict(foo='bar')</span></tt>.</p> </dd></dl> <dl class="class"> <dt id="cycler"> <em class="property">class </em><tt class="descname">cycler</tt><big>(</big><em>*items</em><big>)</big><a class="headerlink" href="#cycler" title="Permalink to this definition">¶</a></dt> <dd><p>The cycler allows you to cycle among values similar to how <cite>loop.cycle</cite> works. Unlike <cite>loop.cycle</cite> however you can use this cycler outside of loops or over multiple loops.</p> <p>This is for example very useful if you want to show a list of folders and files, with the folders on top, but both in the same list with alternating row colors.</p> <p>The following example shows how <cite>cycler</cite> can be used:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">set</span> <span class="nv">row_class</span> <span class="o">=</span> <span class="nv">cycler</span><span class="o">(</span><span class="s1">'odd'</span><span class="o">,</span> <span class="s1">'even'</span><span class="o">)</span> <span class="cp">%}</span> <span class="nt"><ul</span> <span class="na">class=</span><span class="s">"browser"</span><span class="nt">></span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">folder</span> <span class="k">in</span> <span class="nv">folders</span> <span class="cp">%}</span> <span class="nt"><li</span> <span class="na">class=</span><span class="s">"folder </span><span class="cp">{{</span> <span class="nv">row_class.next</span><span class="o">()</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">folder</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">for</span> <span class="nv">filename</span> <span class="k">in</span> <span class="nv">files</span> <span class="cp">%}</span> <span class="nt"><li</span> <span class="na">class=</span><span class="s">"file </span><span class="cp">{{</span> <span class="nv">row_class.next</span><span class="o">()</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">filename</span><span class="o">|</span><span class="nf">e</span> <span class="cp">}}</span><span class="nt"></li></span> <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> <span class="nt"></ul></span> </pre></div> </div> <p>A cycler has the following attributes and methods:</p> <dl class="method"> <dt id="cycler.reset"> <tt class="descname">reset</tt><big>(</big><big>)</big><a class="headerlink" href="#cycler.reset" title="Permalink to this definition">¶</a></dt> <dd><p>Resets the cycle to the first item.</p> </dd></dl> <dl class="method"> <dt id="cycler.next"> <tt class="descname">next</tt><big>(</big><big>)</big><a class="headerlink" href="#cycler.next" title="Permalink to this definition">¶</a></dt> <dd><p>Goes one item a head and returns the then current item.</p> </dd></dl> <dl class="attribute"> <dt id="cycler.current"> <tt class="descname">current</tt><a class="headerlink" href="#cycler.current" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the current item.</p> </dd></dl> <p><strong>new in Jinja 2.1</strong></p> </dd></dl> <dl class="class"> <dt id="joiner"> <em class="property">class </em><tt class="descname">joiner</tt><big>(</big><em>sep='</em>, <em>'</em><big>)</big><a class="headerlink" href="#joiner" title="Permalink to this definition">¶</a></dt> <dd><p>A tiny helper that can be use to “join” multiple sections. A joiner is passed a string and will return that string every time it’s called, except the first time in which situation it returns an empty string. You can use this to join things:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">set</span> <span class="nv">pipe</span> <span class="o">=</span> <span class="nv">joiner</span><span class="o">(</span><span class="s2">"|"</span><span class="o">)</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">if</span> <span class="nv">categories</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">pipe</span><span class="o">()</span> <span class="cp">}}</span> Categories: <span class="cp">{{</span> <span class="nv">categories</span><span class="o">|</span><span class="nf">join</span><span class="o">(</span><span class="s2">", "</span><span class="o">)</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">if</span> <span class="nv">author</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">pipe</span><span class="o">()</span> <span class="cp">}}</span> Author: <span class="cp">{{</span> <span class="nv">author</span><span class="o">()</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">if</span> <span class="nv">can_edit</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">pipe</span><span class="o">()</span> <span class="cp">}}</span> <span class="nt"><a</span> <span class="na">href=</span><span class="s">"?action=edit"</span><span class="nt">></span>Edit<span class="nt"></a></span> <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span> </pre></div> </div> <p><strong>new in Jinja 2.1</strong></p> </dd></dl> </div> <div class="section" id="extensions"> <h2>Extensions<a class="headerlink" href="#extensions" title="Permalink to this headline">¶</a></h2> <p>The following sections cover the built-in Jinja2 extensions that may be enabled by the application. The application could also provide further extensions not covered by this documentation. In that case there should be a separate document explaining the extensions.</p> <div class="section" id="i18n"> <span id="i18n-in-templates"></span><h3>i18n<a class="headerlink" href="#i18n" title="Permalink to this headline">¶</a></h3> <p>If the i18n extension is enabled it’s possible to mark parts in the template as translatable. To mark a section as translatable you can use <cite>trans</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><p></span><span class="cp">{%</span> <span class="k">trans</span> <span class="cp">%}</span>Hello <span class="cp">{{</span> <span class="nv">user</span> <span class="cp">}}</span>!<span class="cp">{%</span> <span class="k">endtrans</span> <span class="cp">%}</span><span class="nt"></p></span> </pre></div> </div> <p>To translate a template expression — say, using template filters or just accessing an attribute of an object — you need to bind the expression to a name for use within the translation block:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="nt"><p></span><span class="cp">{%</span> <span class="k">trans</span> <span class="nv">user</span><span class="o">=</span><span class="nv">user.username</span> <span class="cp">%}</span>Hello <span class="cp">{{</span> <span class="nv">user</span> <span class="cp">}}</span>!<span class="cp">{%</span> <span class="k">endtrans</span> <span class="cp">%}</span><span class="nt"></p></span> </pre></div> </div> <p>If you need to bind more than one expression inside a <cite>trans</cite> tag, separate the pieces with a comma (<tt class="docutils literal"><span class="pre">,</span></tt>):</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="nv">book_title</span><span class="o">=</span><span class="nv">book.title</span><span class="o">,</span> <span class="nv">author</span><span class="o">=</span><span class="nv">author.name</span> <span class="cp">%}</span> This is <span class="cp">{{</span> <span class="nv">book_title</span> <span class="cp">}}</span> by <span class="cp">{{</span> <span class="nv">author</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endtrans</span> <span class="cp">%}</span> </pre></div> </div> <p>Inside trans tags no statements are allowed, only variable tags are.</p> <p>To pluralize, specify both the singular and plural forms with the <cite>pluralize</cite> tag, which appears between <cite>trans</cite> and <cite>endtrans</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="nv">count</span><span class="o">=</span><span class="nv">list</span><span class="o">|</span><span class="nf">length</span> <span class="cp">%}</span> There is <span class="cp">{{</span> <span class="nv">count</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span> object. <span class="cp">{%</span> <span class="k">pluralize</span> <span class="cp">%}</span> There are <span class="cp">{{</span> <span class="nv">count</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span> objects. <span class="cp">{%</span> <span class="k">endtrans</span> <span class="cp">%}</span> </pre></div> </div> <p>Per default the first variable in a block is used to determine the correct singular or plural form. If that doesn’t work out you can specify the name which should be used for pluralizing by adding it as parameter to <cite>pluralize</cite>:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="p">...</span><span class="o">,</span> <span class="nv">user_count</span><span class="o">=</span><span class="nv">users</span><span class="o">|</span><span class="nf">length</span> <span class="cp">%}</span>... <span class="cp">{%</span> <span class="k">pluralize</span> <span class="nv">user_count</span> <span class="cp">%}</span>...<span class="cp">{%</span> <span class="k">endtrans</span> <span class="cp">%}</span> </pre></div> </div> <p>It’s also possible to translate strings in expressions. For that purpose three functions exist:</p> <p>_ <cite>gettext</cite>: translate a single string - <cite>ngettext</cite>: translate a pluralizable string - <cite>_</cite>: alias for <cite>gettext</cite></p> <p>For example you can print a translated string easily this way:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="kp">_</span><span class="o">(</span><span class="s1">'Hello World!'</span><span class="o">)</span> <span class="cp">}}</span> </pre></div> </div> <p>To use placeholders you can use the <cite>format</cite> filter:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="kp">_</span><span class="o">(</span><span class="s1">'Hello %(user)s!'</span><span class="o">)|</span><span class="nf">format</span><span class="o">(</span><span class="nv">user</span><span class="o">=</span><span class="nv">user.username</span><span class="o">)</span> <span class="cp">}}</span> </pre></div> </div> <p>For multiple placeholders always use keyword arguments to <cite>format</cite> as other languages may not use the words in the same order.</p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.5.</span></p> <p>If newstyle gettext calls are activated (<a class="reference internal" href="extensions.html#newstyle-gettext"><em>Newstyle Gettext</em></a>), using placeholders is a lot easier:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{{</span> <span class="nv">gettext</span><span class="o">(</span><span class="s1">'Hello World!'</span><span class="o">)</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">gettext</span><span class="o">(</span><span class="s1">'Hello %(name)s!'</span><span class="o">,</span> <span class="nv">name</span><span class="o">=</span><span class="s1">'World'</span><span class="o">)</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">ngettext</span><span class="o">(</span><span class="s1">'%(num)d apple'</span><span class="o">,</span> <span class="s1">'%(num)d apples'</span><span class="o">,</span> <span class="nv">apples</span><span class="o">|</span><span class="nf">count</span><span class="o">)</span> <span class="cp">}}</span> </pre></div> </div> <p>Note that the <cite>ngettext</cite> function’s format string automatically receives the count as <cite>num</cite> parameter additionally to the regular parameters.</p> </div> <div class="section" id="expression-statement"> <h3>Expression Statement<a class="headerlink" href="#expression-statement" title="Permalink to this headline">¶</a></h3> <p>If the expression-statement extension is loaded a tag called <cite>do</cite> is available that works exactly like the regular variable expression (<tt class="docutils literal"><span class="pre">{{</span> <span class="pre">...</span> <span class="pre">}}</span></tt>) just that it doesn’t print anything. This can be used to modify lists:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">do</span> <span class="nv">navigation.append</span><span class="o">(</span><span class="s1">'a string'</span><span class="o">)</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="loop-controls"> <h3>Loop Controls<a class="headerlink" href="#loop-controls" title="Permalink to this headline">¶</a></h3> <p>If the application enables the <a class="reference internal" href="extensions.html#loopcontrols-extension"><em>Loop Controls</em></a> it’s possible to use <cite>break</cite> and <cite>continue</cite> in loops. When <cite>break</cite> is reached, the loop is terminated; if <cite>continue</cite> is reached, the processing is stopped and continues with the next iteration.</p> <p>Here a loop that skips every second item:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="cp">{%</span>- <span class="k">if</span> <span class="nb">loop</span><span class="nv">.index</span> <span class="k">is</span> <span class="nf">even</span> <span class="cp">%}{%</span> <span class="k">continue</span> <span class="cp">%}{%</span> <span class="k">endif</span> <span class="cp">%}</span> ... <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> <p>Likewise a look that stops processing after the 10th iteration:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">for</span> <span class="nv">user</span> <span class="k">in</span> <span class="nv">users</span> <span class="cp">%}</span> <span class="cp">{%</span>- <span class="k">if</span> <span class="nb">loop</span><span class="nv">.index</span> <span class="o">>=</span> <span class="m">10</span> <span class="cp">%}{%</span> <span class="k">break</span> <span class="cp">%}{%</span> <span class="k">endif</span> <span class="cp">%}</span> <span class="cp">{%</span>- <span class="k">endfor</span> <span class="cp">%}</span> </pre></div> </div> </div> <div class="section" id="with-statement"> <h3>With Statement<a class="headerlink" href="#with-statement" title="Permalink to this headline">¶</a></h3> <p class="versionadded"> <span class="versionmodified">New in version 2.3.</span></p> <p>If the application enables the <a class="reference internal" href="extensions.html#with-extension"><em>With Statement</em></a> it is possible to use the <cite>with</cite> keyword in templates. This makes it possible to create a new inner scope. Variables set within this scope are not visible outside of the scope.</p> <p>With in a nutshell:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">with</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">set</span> <span class="nv">foo</span> <span class="o">=</span> <span class="m">42</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">foo</span> <span class="cp">}}</span> foo is 42 here <span class="cp">{%</span> <span class="k">endwith</span> <span class="cp">%}</span> foo is not visible here any longer </pre></div> </div> <p>Because it is common to set variables at the beginning of the scope you can do that within the with statement. The following two examples are equivalent:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">with</span> <span class="nv">foo</span> <span class="o">=</span> <span class="m">42</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">foo</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endwith</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">with</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">set</span> <span class="nv">foo</span> <span class="o">=</span> <span class="m">42</span> <span class="cp">%}</span> <span class="cp">{{</span> <span class="nv">foo</span> <span class="cp">}}</span> <span class="cp">{%</span> <span class="k">endwith</span> <span class="cp">%}</span> </pre></div> </div> </div> </div> <div class="section" id="autoescape-extension"> <span id="autoescape-overrides"></span><h2>Autoescape Extension<a class="headerlink" href="#autoescape-extension" title="Permalink to this headline">¶</a></h2> <p class="versionadded"> <span class="versionmodified">New in version 2.4.</span></p> <p>If the application enables the <a class="reference internal" href="extensions.html#autoescape-extension"><em>Autoescape Extension</em></a> one can activate and deactivate the autoescaping from within the templates.</p> <p>Example:</p> <div class="highlight-html+jinja"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">autoescape</span> <span class="kp">true</span> <span class="cp">%}</span> Autoescaping is active within this block <span class="cp">{%</span> <span class="k">endautoescape</span> <span class="cp">%}</span> <span class="cp">{%</span> <span class="k">autoescape</span> <span class="kp">false</span> <span class="cp">%}</span> Autoescaping is inactive within this block <span class="cp">{%</span> <span class="k">endautoescape</span> <span class="cp">%}</span> </pre></div> </div> <p>After the <cite>endautoescape</cite> the behavior is reverted to what it was before.</p> </div> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"><p class="logo"><a href="index.html"> <img class="logo" src="_static/jinja-small.png" alt="Logo"/> </a></p> <h3><a href="index.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">Template Designer Documentation</a><ul> <li><a class="reference internal" href="#synopsis">Synopsis</a></li> <li><a class="reference internal" href="#variables">Variables</a></li> <li><a class="reference internal" href="#filters">Filters</a></li> <li><a class="reference internal" href="#tests">Tests</a></li> <li><a class="reference internal" href="#comments">Comments</a></li> <li><a class="reference internal" href="#whitespace-control">Whitespace Control</a></li> <li><a class="reference internal" href="#escaping">Escaping</a></li> <li><a class="reference internal" href="#line-statements">Line Statements</a></li> <li><a class="reference internal" href="#template-inheritance">Template Inheritance</a><ul> <li><a class="reference internal" href="#base-template">Base Template</a></li> <li><a class="reference internal" href="#child-template">Child Template</a></li> <li><a class="reference internal" href="#super-blocks">Super Blocks</a></li> <li><a class="reference internal" href="#named-block-end-tags">Named Block End-Tags</a></li> <li><a class="reference internal" href="#block-nesting-and-scope">Block Nesting and Scope</a></li> <li><a class="reference internal" href="#template-objects">Template Objects</a></li> </ul> </li> <li><a class="reference internal" href="#html-escaping">HTML Escaping</a><ul> <li><a class="reference internal" href="#working-with-manual-escaping">Working with Manual Escaping</a></li> <li><a class="reference internal" href="#working-with-automatic-escaping">Working with Automatic Escaping</a></li> </ul> </li> <li><a class="reference internal" href="#list-of-control-structures">List of Control Structures</a><ul> <li><a class="reference internal" href="#for">For</a></li> <li><a class="reference internal" href="#if">If</a></li> <li><a class="reference internal" href="#macros">Macros</a></li> <li><a class="reference internal" href="#call">Call</a></li> <li><a class="reference internal" href="#id9">Filters</a></li> <li><a class="reference internal" href="#assignments">Assignments</a></li> <li><a class="reference internal" href="#extends">Extends</a></li> <li><a class="reference internal" href="#block">Block</a></li> <li><a class="reference internal" href="#include">Include</a></li> <li><a class="reference internal" href="#import">Import</a></li> </ul> </li> <li><a class="reference internal" href="#import-context-behavior">Import Context Behavior</a></li> <li><a class="reference internal" href="#expressions">Expressions</a><ul> <li><a class="reference internal" href="#literals">Literals</a></li> <li><a class="reference internal" href="#math">Math</a></li> <li><a class="reference internal" href="#comparisons">Comparisons</a></li> <li><a class="reference internal" href="#logic">Logic</a></li> <li><a class="reference internal" href="#other-operators">Other Operators</a></li> <li><a class="reference internal" href="#if-expression">If Expression</a></li> </ul> </li> <li><a class="reference internal" href="#list-of-builtin-filters">List of Builtin Filters</a></li> <li><a class="reference internal" href="#list-of-builtin-tests">List of Builtin Tests</a></li> <li><a class="reference internal" href="#list-of-global-functions">List of Global Functions</a></li> <li><a class="reference internal" href="#extensions">Extensions</a><ul> <li><a class="reference internal" href="#i18n">i18n</a></li> <li><a class="reference internal" href="#expression-statement">Expression Statement</a></li> <li><a class="reference internal" href="#loop-controls">Loop Controls</a></li> <li><a class="reference internal" href="#with-statement">With Statement</a></li> </ul> </li> <li><a class="reference internal" href="#autoescape-extension">Autoescape Extension</a></li> </ul> </li> </ul> <h3>Related Topics</h3> <ul> <li><a href="index.html">Documentation overview</a><ul> <li>Previous: <a href="sandbox.html" title="previous chapter">Sandbox</a></li> <li>Next: <a href="extensions.html" title="next chapter">Extensions</a></li> </ul></li> </ul> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="_sources/templates.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script 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