================================================== The Django template language: For template authors ================================================== Django's template language is designed to strike a balance between power and ease. It's designed to feel comfortable to those used to working with HTML. If you have any exposure to other text-based template languages, such as Smarty_ or CheetahTemplate_, you should feel right at home with Django's templates. .. _Smarty: http://smarty.php.net/ .. _CheetahTemplate: http://www.cheetahtemplate.org/ Templates ========= A template is simply a text file. It can generate any text-based format (HTML, XML, CSV, etc.). A template contains **variables**, which get replaced with values when the template is evaluated, and **tags**, which control the logic of the template. Below is a minimal template that illustrates a few basics. Each element will be explained later in this document.:: {% extends "base_generic.html" %} {% block title %}{{ section.title }}{% endblock %} {% block content %}

{{ section.title }}

{% for story in story_list %}

{{ story.headline|upper }}

{{ story.tease|truncatewords:"100" }}

{% endfor %} {% endblock %} .. admonition:: Philosophy Why use a text-based template instead of an XML-based one (like Zope's TAL)? We wanted Django's template language to be usable for more than just XML/HTML templates. At World Online, we use it for e-mails, JavaScript and CSV. You can use the template language for any text-based format. Oh, and one more thing: Making humans edit XML is sadistic! Variables ========= Variables look like this: ``{{ variable }}``. When the template engine encounters a variable, it evaluates that variable and replaces it with the result. Use a dot (``.``) to access attributes of a variable. .. admonition:: Behind the scenes Technically, when the template system encounters a dot, it tries the following lookups, in this order: * Dictionary lookup * Attribute lookup * Method call * List-index lookup In the above example, ``{{ section.title }}`` will be replaced with the ``title`` attribute of the ``section`` object. If you use a variable that doesn't exist, the template system will insert the value of the ``TEMPLATE_STRING_IF_INVALID`` setting, which is set to ``''`` (the empty string) by default. See `Using the built-in reference`_, below, for help on finding what variables are available in a given template. Filters ======= You can modify variables for display by using **filters**. Filters look like this: ``{{ name|lower }}``. This displays the value of the ``{{ name }}`` variable after being filtered through the ``lower`` filter, which converts text to lowercase. Use a pipe (``|``) to apply a filter. Filters can be "chained." The output of one filter is applied to the next. ``{{ text|escape|linebreaks }}`` is a common idiom for escaping text contents, then converting line breaks to ``

`` tags. Some filters take arguments. A filter argument looks like this: ``{{ bio|truncatewords:30 }}``. This will display the first 30 words of the ``bio`` variable. Filter arguments that contain spaces must be quoted; for example, to join a list with commas and spaced you'd use ``{{ list|join:", " }}``. The `Built-in filter reference`_ below describes all the built-in filters. Tags ==== Tags look like this: ``{% tag %}``. Tags are more complex than variables: Some create text in the output, some control flow by performing loops or logic, and some load external information into the template to be used by later variables. Some tags require beginning and ending tags (i.e. ``{% tag %} ... tag contents ... {% endtag %}``). The `Built-in tag reference`_ below describes all the built-in tags. You can create your own tags, if you know how to write Python code. Comments ======== To comment-out part of a line in a template, use the comment syntax: ``{# #}``. For example, this template would render as ``'hello'``:: {# greeting #}hello A comment can contain any template code, invalid or not. For example:: {# {% if foo %}bar{% else %} #} This syntax can only be used for single-line comments (no newlines are permitted between the ``{#`` and ``#}`` delimiters). If you need to comment out a multiline portion of the template, see the ``comment`` tag, below__. __ comment_ Template inheritance ==================== The most powerful -- and thus the most complex -- part of Django's template engine is template inheritance. Template inheritance allows you to build a base "skeleton" template that contains all the common elements of your site and defines **blocks** that child templates can override. It's easiest to understand template inheritance by starting with an example:: {% block title %}My amazing site{% endblock %}

{% block content %}{% endblock %}
This template, which we'll call ``base.html``, 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. In this example, the ``{% block %}`` tag defines three blocks that child templates can fill in. All the ``block`` tag does is to tell the template engine that a child template may override those portions of the template. A child template might look like this:: {% extends "base.html" %} {% block title %}My amazing blog{% endblock %} {% block content %} {% for entry in blog_entries %}

{{ entry.title }}

{{ entry.body }}

{% endfor %} {% endblock %} The ``{% extends %}`` 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 -- in this case, "base.html". At that point, the template engine will notice the three ``{% block %}`` tags in ``base.html`` and replace those blocks with the contents of the child template. Depending on the value of ``blog_entries``, the output might look like:: My amazing blog

Entry one

This is my first entry.

Entry two

This is my second entry.

Note that since the child template didn't define the ``sidebar`` block, the value from the parent template is used instead. Content within a ``{% block %}`` tag in a parent template is always used as a fallback. You can use as many levels of inheritance as needed. One common way of using inheritance is the following three-level approach: * Create a ``base.html`` template that holds the main look-and-feel of your site. * Create a ``base_SECTIONNAME.html`` template for each "section" of your site. For example, ``base_news.html``, ``base_sports.html``. These templates all extend ``base.html`` and include section-specific styles/design. * Create individual templates for each type of page, such as a news article or blog entry. These templates extend the appropriate section template. This approach maximizes code reuse and makes it easy to add items to shared content areas, such as section-wide navigation. Here are some tips for working with inheritance: * If you use ``{% extends %}`` in a template, it must be the first template tag in that template. Template inheritance won't work, otherwise. * More ``{% block %}`` tags in your base templates are better. Remember, child templates don't have to define all parent blocks, so you can fill in reasonable defaults in a number of blocks, then only define the ones you need later. It's better to have more hooks than fewer hooks. * If you find yourself duplicating content in a number of templates, it probably means you should move that content to a ``{% block %}`` in a parent template. * If you need to get the content of the block from the parent template, the ``{{ block.super }}`` variable will do the trick. This is useful if you want to add to the contents of a parent block instead of completely overriding it. * For extra readability, you can optionally give a *name* to your ``{% endblock %}`` tag. For example:: {% block content %} ... {% endblock content %} In larger templates, this technique helps you see which ``{% block %}`` tags are being closed. Finally, note that you can't define multiple ``{% block %}`` 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 *parent*. If there were two similarly-named ``{% block %}`` tags in a template, that template's parent wouldn't know which one of the blocks' content to use. Using the built-in reference ============================ Django's admin interface includes a complete reference of all template tags and filters available for a given site. To see it, go to your admin interface and click the "Documentation" link in the upper right of the page. The reference is divided into 4 sections: tags, filters, models, and views. The **tags** and **filters** sections describe all the built-in tags (in fact, the tag and filter references below come directly from those pages) as well as any custom tag or filter libraries available. The **views** page is the most valuable. Each URL in your site has a separate entry here, and clicking on a URL will show you: * The name of the view function that generates that view. * A short description of what the view does. * The **context**, or a list of variables available in the view's template. * The name of the template or templates that are used for that view. Each view documentation page also has a bookmarklet that you can use to jump from any page to the documentation page for that view. Because Django-powered sites usually use database objects, the **models** section of the documentation page describes each type of object in the system along with all the fields available on that object. Taken together, the documentation pages should tell you every tag, filter, variable and object available to you in a given template. Custom tag and filter libraries =============================== Certain applications provide custom tag and filter libraries. To access them in a template, use the ``{% load %}`` tag:: {% load comments %} {% comment_form for blogs.entries entry.id with is_public yes %} In the above, the ``load`` tag loads the ``comments`` tag library, which then makes the ``comment_form`` tag available for use. Consult the documentation area in your admin to find the list of custom libraries in your installation. The ``{% load %}`` tag can take multiple library names, separated by spaces. Example:: {% load comments i18n %} Custom libraries and template inheritance ----------------------------------------- When you load a custom tag or filter library, the tags/filters are only made available to the current template -- not any parent or child templates along the template-inheritance path. For example, if a template ``foo.html`` has ``{% load comments %}``, a child template (e.g., one that has ``{% extends "foo.html" %}``) will *not* have access to the comments template tags and filters. The child template is responsible for its own ``{% load comments %}``. This is a feature for the sake of maintainability and sanity. Built-in tag and filter reference ================================= For those without an admin site available, reference for the stock tags and filters follows. Because Django is highly customizable, the reference in your admin should be considered the final word on what tags and filters are available, and what they do. Built-in tag reference ---------------------- block ~~~~~ Define a block that can be overridden by child templates. See `Template inheritance`_ for more information. comment ~~~~~~~ Ignore everything between ``{% comment %}`` and ``{% endcomment %}`` cycle ~~~~~ **Changed in Django development version** Cycle among the given strings or variables each time this tag is encountered. Within a loop, cycles among the given strings/variables each time through the loop:: {% for o in some_list %} ... {% endfor %} Outside of a loop, give the values a unique name the first time you call it, then use that name each successive time through:: ... ... ... You can use any number of values, separated by spaces. Values enclosed in single (') or double quotes (") are treated as string literals, while values without quotes are assumed to refer to context variables. You can also separate values with commas:: {% cycle row1,row2,row3 %} In this syntax, each value will be interpreted as literal text. The comma-based syntax exists for backwards-compatibility, and should not be used for new projects. debug ~~~~~ Output a whole load of debugging information, including the current context and imported modules. extends ~~~~~~~ Signal that this template extends a parent template. This tag can be used in two ways: * ``{% extends "base.html" %}`` (with quotes) uses the literal value ``"base.html"`` as the name of the parent template to extend. * ``{% extends variable %}`` uses the value of ``variable``. If the variable evaluates to a string, Django will use that string as the name of the parent template. If the variable evaluates to a ``Template`` object, Django will use that object as the parent template. See `Template inheritance`_ for more information. filter ~~~~~~ Filter the contents of the variable through variable filters. Filters can also be piped through each other, and they can have arguments -- just like in variable syntax. Sample usage:: {% filter escape|lower %} This text will be HTML-escaped, and will appear in all lowercase. {% endfilter %} firstof ~~~~~~~ Outputs the first variable passed that is not False. Outputs nothing if all the passed variables are False. Sample usage:: {% firstof var1 var2 var3 %} This is equivalent to:: {% if var1 %} {{ var1 }} {% else %}{% if var2 %} {{ var2 }} {% else %}{% if var3 %} {{ var3 }} {% endif %}{% endif %}{% endif %} for ~~~ Loop over each item in an array. For example, to display a list of athletes provided in ``athlete_list``:: You can loop over a list in reverse by using ``{% for obj in list reversed %}``. **New in Django development version** If you need to loop over a list of lists, you can unpack the values in eachs sub-list into a set of known names. For example, if your context contains a list of (x,y) coordinates called ``points``, you could use the following to output the list of points:: {% for x, y in points %} There is a point at {{ x }},{{ y }} {% endfor %} This can also be useful if you need to access the items in a dictionary. For example, if your context contained a dictionary ``data``, the following would display the keys and values of the dictionary:: {% for key, value in data.items %} {{ key }}: {{ value }} {% endfor %} The for loop sets a number of variables available within the loop: ========================== ================================================ Variable Description ========================== ================================================ ``forloop.counter`` The current iteration of the loop (1-indexed) ``forloop.counter0`` The current iteration of the loop (0-indexed) ``forloop.revcounter`` The number of iterations from the end of the loop (1-indexed) ``forloop.revcounter0`` The number of iterations from the end of the loop (0-indexed) ``forloop.first`` True if this is the first time through the loop ``forloop.last`` True if this is the last time through the loop ``forloop.parentloop`` For nested loops, this is the loop "above" the current one ========================== ================================================ if ~~ The ``{% if %}`` tag evaluates a variable, and if that variable is "true" (i.e. exists, is not empty, and is not a false boolean value) the contents of the block are output:: {% if athlete_list %} Number of athletes: {{ athlete_list|length }} {% else %} No athletes. {% endif %} In the above, if ``athlete_list`` is not empty, the number of athletes will be displayed by the ``{{ athlete_list|length }}`` variable. As you can see, the ``if`` tag can take an optional ``{% else %}`` clause that will be displayed if the test fails. ``if`` tags may use ``and``, ``or`` or ``not`` to test a number of variables or to negate a given variable:: {% if athlete_list and coach_list %} Both athletes and coaches are available. {% endif %} {% if not athlete_list %} There are no athletes. {% endif %} {% if athlete_list or coach_list %} There are some athletes or some coaches. {% endif %} {% if not athlete_list or coach_list %} There are no athletes or there are some coaches (OK, so writing English translations of boolean logic sounds stupid; it's not our fault). {% endif %} {% if athlete_list and not coach_list %} There are some athletes and absolutely no coaches. {% endif %} ``if`` tags don't allow ``and`` and ``or`` clauses within the same tag, because the order of logic would be ambiguous. For example, this is invalid:: {% if athlete_list and coach_list or cheerleader_list %} If you need to combine ``and`` and ``or`` to do advanced logic, just use nested ``if`` tags. For example:: {% if athlete_list %} {% if coach_list or cheerleader_list %} We have athletes, and either coaches or cheerleaders! {% endif %} {% endif %} Multiple uses of the same logical operator are fine, as long as you use the same operator. For example, this is valid:: {% if athlete_list or coach_list or parent_list or teacher_list %} ifchanged ~~~~~~~~~ Check if a value has changed from the last iteration of a loop. The 'ifchanged' block tag is used within a loop. It has two possible uses. 1. Checks its own rendered contents against its previous state and only displays the content if it has changed. For example, this displays a list of days, only displaying the month if it changes::

Archive for {{ year }}

{% for date in days %} {% ifchanged %}

{{ date|date:"F" }}

{% endifchanged %} {{ date|date:"j" }} {% endfor %} 2. If given a variable, check whether that variable has changed. For example, the following shows the date every time it changes, but only shows the hour if both the hour and the date has changed:: {% for date in days %} {% ifchanged date.date %} {{ date.date }} {% endifchanged %} {% ifchanged date.hour date.date %} {{ date.hour }} {% endifchanged %} {% endfor %} ifequal ~~~~~~~ Output the contents of the block if the two arguments equal each other. Example:: {% ifequal user.id comment.user_id %} ... {% endifequal %} As in the ``{% if %}`` tag, an ``{% else %}`` clause is optional. The arguments can be hard-coded strings, so the following is valid:: {% ifequal user.username "adrian" %} ... {% endifequal %} It is only possible to compare an argument to template variables or strings. You cannot check for equality with Python objects such as ``True`` or ``False``. If you need to test if something is true or false, use the ``if`` tag instead. ifnotequal ~~~~~~~~~~ Just like ``ifequal``, except it tests that the two arguments are not equal. include ~~~~~~~ Loads a template and renders it with the current context. This is a way of "including" other templates within a template. The template name can either be a variable or a hard-coded (quoted) string, in either single or double quotes. This example includes the contents of the template ``"foo/bar.html"``:: {% include "foo/bar.html" %} This example includes the contents of the template whose name is contained in the variable ``template_name``:: {% include template_name %} An included template is rendered with the context of the template that's including it. This example produces the output ``"Hello, John"``: * Context: variable ``person`` is set to ``"john"``. * Template:: {% include "name_snippet.html" %} * The ``name_snippet.html`` template:: Hello, {{ person }} See also: ``{% ssi %}``. load ~~~~ Load a custom template tag set. See `Custom tag and filter libraries`_ for more information. now ~~~ Display the date, formatted according to the given string. Uses the same format as PHP's ``date()`` function (http://php.net/date) with some custom extensions. Available format strings: ================ ======================================== ===================== Format character Description Example output ================ ======================================== ===================== a ``'a.m.'`` or ``'p.m.'`` (Note that ``'a.m.'`` this is slightly different than PHP's output, because this includes periods to match Associated Press style.) A ``'AM'`` or ``'PM'``. ``'AM'`` b Month, textual, 3 letters, lowercase. ``'jan'`` B Not implemented. d Day of the month, 2 digits with ``'01'`` to ``'31'`` leading zeros. D Day of the week, textual, 3 letters. ``'Fri'`` f Time, in 12-hour hours and minutes, ``'1'``, ``'1:30'`` with minutes left off if they're zero. Proprietary extension. F Month, textual, long. ``'January'`` g Hour, 12-hour format without leading ``'1'`` to ``'12'`` zeros. G Hour, 24-hour format without leading ``'0'`` to ``'23'`` zeros. h Hour, 12-hour format. ``'01'`` to ``'12'`` H Hour, 24-hour format. ``'00'`` to ``'23'`` i Minutes. ``'00'`` to ``'59'`` I Not implemented. j Day of the month without leading ``'1'`` to ``'31'`` zeros. l Day of the week, textual, long. ``'Friday'`` L Boolean for whether it's a leap year. ``True`` or ``False`` m Month, 2 digits with leading zeros. ``'01'`` to ``'12'`` M Month, textual, 3 letters. ``'Jan'`` n Month without leading zeros. ``'1'`` to ``'12'`` N Month abbreviation in Associated Press ``'Jan.'``, ``'Feb.'``, ``'March'``, ``'May'`` style. Proprietary extension. O Difference to Greenwich time in hours. ``'+0200'`` P Time, in 12-hour hours, minutes and ``'1 a.m.'``, ``'1:30 p.m.'``, ``'midnight'``, ``'noon'``, ``'12:30 p.m.'`` 'a.m.'/'p.m.', with minutes left off if they're zero and the special-case strings 'midnight' and 'noon' if appropriate. Proprietary extension. r RFC 822 formatted date. ``'Thu, 21 Dec 2000 16:01:07 +0200'`` s Seconds, 2 digits with leading zeros. ``'00'`` to ``'59'`` S English ordinal suffix for day of the ``'st'``, ``'nd'``, ``'rd'`` or ``'th'`` month, 2 characters. t Number of days in the given month. ``28`` to ``31`` T Time zone of this machine. ``'EST'``, ``'MDT'`` U Not implemented. w Day of the week, digits without ``'0'`` (Sunday) to ``'6'`` (Saturday) leading zeros. W ISO-8601 week number of year, with ``1``, ``23`` weeks starting on Monday. y Year, 2 digits. ``'99'`` Y Year, 4 digits. ``'1999'`` z Day of the year. ``0`` to ``365`` Z Time zone offset in seconds. The ``-43200`` to ``43200`` offset for timezones west of UTC is always negative, and for those east of UTC is always positive. ================ ======================================== ===================== Example:: It is {% now "jS F Y H:i" %} Note that you can backslash-escape a format string if you want to use the "raw" value. In this example, "f" is backslash-escaped, because otherwise "f" is a format string that displays the time. The "o" doesn't need to be escaped, because it's not a format character:: It is the {% now "jS o\f F" %} This would display as "It is the 4th of September". regroup ~~~~~~~ Regroup a list of alike objects by a common attribute. This complex tag is best illustrated by use of an example: say that ``people`` is a list of people represented by dictionaries with ``first_name``, ``last_name``, and ``gender`` keys:: people = [ {'first_name': 'George', 'last_name': 'Bush', 'gender': 'Male'}, {'first_name': 'Bill', 'last_name': 'Clinton', 'gender': 'Male'}, {'first_name': 'Margaret', 'last_name': 'Thatcher', 'gender': 'Female'}, {'first_name': 'Condoleezza', 'last_name': 'Rice', 'gender': 'Female'}, {'first_name': 'Pat', 'last_name': 'Smith', 'gender': 'Unknown'}, ] ...and you'd like to display a hierarchical list that is ordered by gender, like this: * Male: * George Bush * Bill Clinton * Female: * Margaret Thatcher * Condoleezza Rice * Unknown: * Pat Smith You can use the ``{% regroup %}`` tag to group the list of people by gender. The following snippet of template code would accomplish this:: {% regroup people by gender as gender_list %} Let's walk through this example. ``{% regroup %}`` takes three arguments: the list you want to regroup, the attribute to group by, and the name of the resulting list. Here, we're regrouping the ``people`` list by the ``gender`` attribute and calling the result ``gender_list``. ``{% regroup %}`` produces a list (in this case, ``gender_list``) of **group objects**. Each group object has two attributes: * ``grouper`` -- the item that was grouped by (e.g., the string "Male" or "Female"). * ``list`` -- a list of all items in this group (e.g., a list of all people with gender='Male'). Note that ``{% regroup %}`` does not order its input! Our example relies on the fact that the ``people`` list was ordered by ``gender`` in the first place. If the ``people`` list did *not* order its members by ``gender``, the regrouping would naively display more than one group for a single gender. For example, say the ``people`` list was set to this (note that the males are not grouped together):: people = [ {'first_name': 'Bill', 'last_name': 'Clinton', 'gender': 'Male'}, {'first_name': 'Pat', 'last_name': 'Smith', 'gender': 'Unknown'}, {'first_name': 'Margaret', 'last_name': 'Thatcher', 'gender': 'Female'}, {'first_name': 'George', 'last_name': 'Bush', 'gender': 'Male'}, {'first_name': 'Condoleezza', 'last_name': 'Rice', 'gender': 'Female'}, ] With this input for ``people``, the example ``{% regroup %}`` template code above would result in the following output: * Male: * Bill Clinton * Unknown: * Pat Smith * Female: * Margaret Thatcher * Male: * George Bush * Female: * Condoleezza Rice The easiest solution to this gotcha is to make sure in your view code that the data is ordered according to how you want to display it. Another solution is to sort the data in the template using the ``dictsort`` filter, if your data is in a list of dictionaries:: {% regroup people|dictsort:"gender" by gender as gender_list %} spaceless ~~~~~~~~~ Removes whitespace between HTML tags. This includes tab characters and newlines. Example usage:: {% spaceless %}


{% endspaceless %} This example would return this HTML::


Only space between *tags* is removed -- not space between tags and text. In this example, the space around ``Hello`` won't be stripped:: {% spaceless %} Hello {% endspaceless %} ssi ~~~ Output the contents of a given file into the page. Like a simple "include" tag, ``{% ssi %}`` includes the contents of another file -- which must be specified using an absolute path -- in the current page:: {% ssi /home/html/ljworld.com/includes/right_generic.html %} If the optional "parsed" parameter is given, the contents of the included file are evaluated as template code, within the current context:: {% ssi /home/html/ljworld.com/includes/right_generic.html parsed %} Note that if you use ``{% ssi %}``, you'll need to define `ALLOWED_INCLUDE_ROOTS`_ in your Django settings, as a security measure. See also: ``{% include %}``. .. _ALLOWED_INCLUDE_ROOTS: ../settings/#allowed-include-roots templatetag ~~~~~~~~~~~ Output one of the syntax characters used to compose template tags. Since the template system has no concept of "escaping", to display one of the bits used in template tags, you must use the ``{% templatetag %}`` tag. The argument tells which template bit to output: ================== ======= Argument Outputs ================== ======= ``openblock`` ``{%`` ``closeblock`` ``%}`` ``openvariable`` ``{{`` ``closevariable`` ``}}`` ``openbrace`` ``{`` ``closebrace`` ``}`` ``opencomment`` ``{#`` ``closecomment`` ``#}`` ================== ======= url ~~~ **Note that the syntax for this tag may change in the future, as we make it more robust.** Returns an absolute URL (i.e., a URL without the domain name) matching a given view function and optional parameters. This is a way to output links without violating the DRY principle by having to hard-code URLs in your templates:: {% url path.to.some_view arg1,arg2,name1=value1 %} The first argument is a path to a view function in the format ``package.package.module.function``. Additional arguments are optional and should be comma-separated values that will be used as positional and keyword arguments in the URL. All arguments required by the URLconf should be present. For example, suppose you have a view, ``app_views.client``, whose URLconf takes a client ID (here, ``client()`` is a method inside the views file ``app_views.py``). The URLconf line might look like this:: ('^client/(\d+)/$', 'app_views.client') If this app's URLconf is included into the project's URLconf under a path such as this:: ('^clients/', include('project_name.app_name.urls')) ...then, in a template, you can create a link to this view like this:: {% url app_views.client client.id %} The template tag will output the string ``/clients/client/123/``. **New in development version:** If you're using `named URL patterns`_, you can refer to the name of the pattern in the ``url`` tag instead of using the path to the view. .. _named URL patterns: ../url_dispatch/#naming-url-patterns widthratio ~~~~~~~~~~ For creating bar charts and such, this tag calculates the ratio of a given value to a maximum value, and then applies that ratio to a constant. For example:: Above, if ``this_value`` is 175 and ``max_value`` is 200, the the image in the above example will be 88 pixels wide (because 175/200 = .875; .875 * 100 = 87.5 which is rounded up to 88). with ~~~~ **New in Django development version** Caches a complex variable under a simpler name. This is useful when accessing an "expensive" method (e.g., one that hits the database) multiple times. For example:: {% with business.employees.count as total %} {{ total }} employee{{ total|pluralize }} {% endwith %} The populated variable (in the example above, ``total``) is only available between the ``{% with %}`` and ``{% endwith %}`` tags. Built-in filter reference ------------------------- add ~~~ Adds the arg to the value. addslashes ~~~~~~~~~~ Adds slashes. Useful for passing strings to JavaScript, for example. capfirst ~~~~~~~~ Capitalizes the first character of the value. center ~~~~~~ Centers the value in a field of a given width. cut ~~~ Removes all values of arg from the given string. date ~~~~ Formats a date according to the given format (same as the `now`_ tag). default ~~~~~~~ If value is unavailable, use given default. default_if_none ~~~~~~~~~~~~~~~ If value is ``None``, use given default. dictsort ~~~~~~~~ Takes a list of dictionaries, returns that list sorted by the key given in the argument. dictsortreversed ~~~~~~~~~~~~~~~~ Takes a list of dictionaries, returns that list sorted in reverse order by the key given in the argument. divisibleby ~~~~~~~~~~~ Returns true if the value is divisible by the argument. escape ~~~~~~ Escapes a string's HTML. Specifically, it makes these replacements: * ``"&"`` to ``"&"`` * ``<`` to ``"<"`` * ``>`` to ``">"`` * ``'"'`` (double quote) to ``'"'`` * ``"'"`` (single quote) to ``'''`` filesizeformat ~~~~~~~~~~~~~~ Format the value like a 'human-readable' file size (i.e. ``'13 KB'``, ``'4.1 MB'``, ``'102 bytes'``, etc). first ~~~~~ Returns the first item in a list. fix_ampersands ~~~~~~~~~~~~~~ Replaces ampersands with ``&`` entities. floatformat ~~~~~~~~~~~ When used without an argument, rounds a floating-point number to one decimal place -- but only if there's a decimal part to be displayed. For example: * ``36.123`` gets converted to ``36.1`` * ``36.15`` gets converted to ``36.2`` * ``36`` gets converted to ``36`` If used with a numeric integer argument, ``floatformat`` rounds a number to that many decimal places. For example: * ``36.1234`` with floatformat:3 gets converted to ``36.123`` * ``36`` with floatformat:4 gets converted to ``36.0000`` If the argument passed to ``floatformat`` is negative, it will round a number to that many decimal places -- but only if there's a decimal part to be displayed. For example: * ``36.1234`` with floatformat:-3 gets converted to ``36.123`` * ``36`` with floatformat:-4 gets converted to ``36`` Using ``floatformat`` with no argument is equivalent to using ``floatformat`` with an argument of ``-1``. get_digit ~~~~~~~~~ Given a whole number, returns the requested digit of it, where 1 is the right-most digit, 2 is the second-right-most digit, etc. Returns the original value for invalid input (if input or argument is not an integer, or if argument is less than 1). Otherwise, output is always an integer. iriencode ~~~~~~~~~ Converts an IRI (Internationalized Resource Identifier) to a string that is suitable for including in a URL. This is necessary if you're trying to use strings containing non-ASCII characters in a URL. It's safe to use this filter on a string that has already gone through the ``urlencode`` filter. join ~~~~ Joins a list with a string, like Python's ``str.join(list)``. length ~~~~~~ Returns the length of the value. Useful for lists. length_is ~~~~~~~~~ Returns a boolean of whether the value's length is the argument. linebreaks ~~~~~~~~~~ Converts newlines into ``

`` and ``
`` tags. linebreaksbr ~~~~~~~~~~~~ Converts newlines into ``
`` tags. linenumbers ~~~~~~~~~~~ Displays text with line numbers. ljust ~~~~~ Left-aligns the value in a field of a given width. **Argument:** field size lower ~~~~~ Converts a string into all lowercase. make_list ~~~~~~~~~ Returns the value turned into a list. For an integer, it's a list of digits. For a string, it's a list of characters. phone2numeric ~~~~~~~~~~~~~ Converts a phone number (possibly containing letters) to its numerical equivalent. For example, ``'800-COLLECT'`` will be converted to ``'800-2655328'``. The input doesn't have to be a valid phone number. This will happily convert any string. pluralize ~~~~~~~~~ Returns a plural suffix if the value is not 1. By default, this suffix is ``'s'``. Example:: You have {{ num_messages }} message{{ num_messages|pluralize }}. For words that require a suffix other than ``'s'``, you can provide an alternate suffix as a parameter to the filter. Example:: You have {{ num_walruses }} walrus{{ num_walrus|pluralize:"es" }}. For words that don't pluralize by simple suffix, you can specify both a singular and plural suffix, separated by a comma. Example:: You have {{ num_cherries }} cherr{{ num_cherries|pluralize:"y,ies" }}. pprint ~~~~~~ A wrapper around pprint.pprint -- for debugging, really. random ~~~~~~ Returns a random item from the list. removetags ~~~~~~~~~~ Removes a space separated list of [X]HTML tags from the output. rjust ~~~~~ Right-aligns the value in a field of a given width. **Argument:** field size slice ~~~~~ Returns a slice of the list. Uses the same syntax as Python's list slicing. See http://diveintopython.org/native_data_types/lists.html#odbchelper.list.slice for an introduction. Example: ``{{ some_list|slice:":2" }}`` slugify ~~~~~~~ Converts to lowercase, removes non-word characters (alphanumerics and underscores) and converts spaces to hyphens. Also strips leading and trailing whitespace. stringformat ~~~~~~~~~~~~ Formats the variable according to the argument, a string formatting specifier. This specifier uses Python string formating syntax, with the exception that the leading "%" is dropped. See http://docs.python.org/lib/typesseq-strings.html for documentation of Python string formatting striptags ~~~~~~~~~ Strips all [X]HTML tags. time ~~~~ Formats a time according to the given format (same as the `now`_ tag). The time filter will only accept parameters in the format string that relate to the time of day, not the date (for obvious reasons). If you need to format a date, use the `date`_ filter. timesince ~~~~~~~~~ Formats a date as the time since that date (i.e. "4 days, 6 hours"). Takes an optional argument that is a variable containing the date to use as the comparison point (without the argument, the comparison point is *now*). For example, if ``blog_date`` is a date instance representing midnight on 1 June 2006, and ``comment_date`` is a date instance for 08:00 on 1 June 2006, then ``{{ comment_date|timesince:blog_date }}`` would return "8 hours". timeuntil ~~~~~~~~~ Similar to ``timesince``, except that it measures the time from now until the given date or datetime. For example, if today is 1 June 2006 and ``conference_date`` is a date instance holding 29 June 2006, then ``{{ conference_date|timeuntil }}`` will return "28 days". Takes an optional argument that is a variable containing the date to use as the comparison point (instead of *now*). If ``from_date`` contains 22 June 2006, then ``{{ conference_date|timeuntil:from_date }}`` will return "7 days". title ~~~~~ Converts a string into titlecase. truncatewords ~~~~~~~~~~~~~ Truncates a string after a certain number of words. **Argument:** Number of words to truncate after truncatewords_html ~~~~~~~~~~~~~~~~~~ Similar to ``truncatewords``, except that it is aware of HTML tags. Any tags that are opened in the string and not closed before the truncation point, are closed immediately after the truncation. This is less efficient than ``truncatewords``, so should only be used when it is being passed HTML text. unordered_list ~~~~~~~~~~~~~~ Recursively takes a self-nested list and returns an HTML unordered list -- WITHOUT opening and closing