1 ==================================================

     2 The Django template language: For template authors

     3 ==================================================

     4 

     5 Django's template language is designed to strike a balance between power and

     6 ease. It's designed to feel comfortable to those used to working with HTML. If

     7 you have any exposure to other text-based template languages, such as Smarty_

     8 or CheetahTemplate_, you should feel right at home with Django's templates.

     9 

    10 .. _Smarty: http://smarty.php.net/

    11 .. _CheetahTemplate: http://www.cheetahtemplate.org/

    12 

    13 Templates

    14 =========

    15 

    16 A template is simply a text file. It can generate any text-based format (HTML,

    17 XML, CSV, etc.).

    18 

    19 A template contains **variables**, which get replaced with values when the

    20 template is evaluated, and **tags**, which control the logic of the template.

    21 

    22 Below is a minimal template that illustrates a few basics. Each element will be

    23 explained later in this document.::

    24 

    25     {% extends "base_generic.html" %}

    26 

    27     {% block title %}{{ section.title }}{% endblock %}

    28 

    29     {% block content %}

    30     <h1>{{ section.title }}</h1>

    31 

    32     {% for story in story_list %}

    33     <h2>

    34       <a href="{{ story.get_absolute_url }}">

    35         {{ story.headline|upper }}

    36       </a>

    37     </h2>

    38     <p>{{ story.tease|truncatewords:"100" }}</p>

    39     {% endfor %}

    40     {% endblock %}

    41 

    42 .. admonition:: Philosophy

    43 

    44     Why use a text-based template instead of an XML-based one (like Zope's

    45     TAL)? We wanted Django's template language to be usable for more than

    46     just XML/HTML templates. At World Online, we use it for e-mails,

    47     JavaScript and CSV. You can use the template language for any text-based

    48     format.

    49 

    50     Oh, and one more thing: Making humans edit XML is sadistic!

    51 

    52 Variables

    53 =========

    54 

    55 Variables look like this: ``{{ variable }}``. When the template engine

    56 encounters a variable, it evaluates that variable and replaces it with the

    57 result.

    58 

    59 Use a dot (``.``) to access attributes of a variable.

    60 

    61 .. admonition:: Behind the scenes

    62 

    63     Technically, when the template system encounters a dot, it tries the

    64     following lookups, in this order:

    65 

    66         * Dictionary lookup

    67         * Attribute lookup

    68         * Method call

    69         * List-index lookup

    70 

    71 In the above example, ``{{ section.title }}`` will be replaced with the

    72 ``title`` attribute of the ``section`` object.

    73 

    74 If you use a variable that doesn't exist, the template system will insert

    75 the value of the ``TEMPLATE_STRING_IF_INVALID`` setting, which is set to ``''``

    76 (the empty string) by default.

    77 

    78 See `Using the built-in reference`_, below, for help on finding what variables

    79 are available in a given template.

    80 

    81 Filters

    82 =======

    83 

    84 You can modify variables for display by using **filters**.

    85 

    86 Filters look like this: ``{{ name|lower }}``. This displays the value of the

    87 ``{{ name }}`` variable after being filtered through the ``lower`` filter,

    88 which converts text to lowercase. Use a pipe (``|``) to apply a filter.

    89 

    90 Filters can be "chained." The output of one filter is applied to the next.

    91 ``{{ text|escape|linebreaks }}`` is a common idiom for escaping text contents,

    92 then converting line breaks to ``<p>`` tags.

    93 

    94 Some filters take arguments. A filter argument looks like this:

    95 ``{{ bio|truncatewords:"30" }}``. This will display the first 30 words of the

    96 ``bio`` variable. Filter arguments always are in double quotes.

    97 

    98 The `Built-in filter reference`_ below describes all the built-in filters.

    99 

   100 Tags

   101 ====

   102 

   103 Tags look like this: ``{% tag %}``. Tags are more complex than variables: Some

   104 create text in the output, some control flow by performing loops or logic, and

   105 some load external information into the template to be used by later variables.

   106 

   107 Some tags require beginning and ending tags (i.e.

   108 ``{% tag %} ... tag contents ... {% endtag %}``). The `Built-in tag reference`_

   109 below describes all the built-in tags. You can create your own tags, if you

   110 know how to write Python code.

   111 

   112 Comments

   113 ========

   114 

   115 To comment-out part of a template, use the comment syntax: ``{# #}``.

   116 

   117 For example, this template would render as ``'hello'``::

   118 

   119     {# greeting #}hello

   120 

   121 A comment can contain any template code, invalid or not. For example::

   122 

   123     {# {% if foo %}bar{% else %} #}

   124 

   125 Template inheritance

   126 ====================

   127 

   128 The most powerful -- and thus the most complex -- part of Django's template

   129 engine is template inheritance. Template inheritance allows you to build a base

   130 "skeleton" template that contains all the common elements of your site and

   131 defines **blocks** that child templates can override.

   132 

   133 It's easiest to understand template inheritance by starting with an example::

   134 

   135     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

   136         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

   137     <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

   138     <head>

   139         <link rel="stylesheet" href="style.css" />

   140         <title>{% block title %}My amazing site{% endblock %}</title>

   141     </head>

   142 

   143     <body>

   144         <div id="sidebar">

   145             {% block sidebar %}

   146             <ul>

   147                 <li><a href="/">Home</a></li>

   148                 <li><a href="/blog/">Blog</a></li>

   149             </ul>

   150             {% endblock %}

   151         </div>

   152 

   153         <div id="content">

   154             {% block content %}{% endblock %}

   155         </div>

   156     </body>

   157     </html>

   158 

   159 This template, which we'll call ``base.html``, defines a simple HTML skeleton

   160 document that you might use for a simple two-column page. It's the job of

   161 "child" templates to fill the empty blocks with content.

   162 

   163 In this example, the ``{% block %}`` tag defines three blocks that child

   164 templates can fill in. All the ``block`` tag does is to tell the template

   165 engine that a child template may override those portions of the template.

   166 

   167 A child template might look like this::

   168 

   169     {% extends "base.html" %}

   170 

   171     {% block title %}My amazing blog{% endblock %}

   172 

   173     {% block content %}

   174     {% for entry in blog_entries %}

   175         <h2>{{ entry.title }}</h2>

   176         <p>{{ entry.body }}</p>

   177     {% endfor %}

   178     {% endblock %}

   179 

   180 The ``{% extends %}`` tag is the key here. It tells the template engine that

   181 this template "extends" another template. When the template system evaluates

   182 this template, first it locates the parent -- in this case, "base.html".

   183 

   184 At that point, the template engine will notice the three ``{% block %}`` tags

   185 in ``base.html`` and replace those blocks with the contents of the child

   186 template. Depending on the value of ``blog_entries``, the output might look

   187 like::

   188 

   189     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

   190         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

   191     <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

   192     <head>

   193         <link rel="stylesheet" href="style.css" />

   194         <title>My amazing blog</title>

   195     </head>

   196 

   197     <body>

   198         <div id="sidebar">

   199             <ul>

   200                 <li><a href="/">Home</a></li>

   201                 <li><a href="/blog/">Blog</a></li>

   202             </ul>

   203         </div>

   204 

   205         <div id="content">

   206             <h2>Entry one</h2>

   207             <p>This is my first entry.</p>

   208 

   209             <h2>Entry two</h2>

   210             <p>This is my second entry.</p>

   211         </div>

   212     </body>

   213     </html>

   214 

   215 Note that since the child template didn't define the ``sidebar`` block, the

   216 value from the parent template is used instead. Content within a ``{% block %}``

   217 tag in a parent template is always used as a fallback.

   218 

   219 You can use as many levels of inheritance as needed. One common way of using

   220 inheritance is the following three-level approach:

   221 

   222     * Create a ``base.html`` template that holds the main look-and-feel of your

   223       site.

   224     * Create a ``base_SECTIONNAME.html`` template for each "section" of your

   225       site. For example, ``base_news.html``, ``base_sports.html``. These

   226       templates all extend ``base.html`` and include section-specific

   227       styles/design.

   228     * Create individual templates for each type of page, such as a news

   229       article or blog entry. These templates extend the appropriate section

   230       template.

   231 

   232 This approach maximizes code reuse and makes it easy to add items to shared

   233 content areas, such as section-wide navigation.

   234 

   235 Here are some tips for working with inheritance:

   236 

   237     * If you use ``{% extends %}`` in a template, it must be the first template

   238       tag in that template. Template inheritance won't work, otherwise.

   239 

   240     * More ``{% block %}`` tags in your base templates are better. Remember,

   241       child templates don't have to define all parent blocks, so you can fill

   242       in reasonable defaults in a number of blocks, then only define the ones

   243       you need later. It's better to have more hooks than fewer hooks.

   244 

   245     * If you find yourself duplicating content in a number of templates, it

   246       probably means you should move that content to a ``{% block %}`` in a

   247       parent template.

   248 

   249     * If you need to get the content of the block from the parent template,

   250       the ``{{ block.super }}`` variable will do the trick. This is useful

   251       if you want to add to the contents of a parent block instead of

   252       completely overriding it.

   253 

   254     * For extra readability, you can optionally give a *name* to your

   255       ``{% endblock %}`` tag. For example::

   256 

   257           {% block content %}

   258           ...

   259           {% endblock content %}

   260 

   261       In larger templates, this technique helps you see which ``{% block %}``

   262       tags are being closed.

   263 

   264 Finally, note that you can't define multiple ``{% block %}`` tags with the same

   265 name in the same template. This limitation exists because a block tag works in

   266 "both" directions. That is, a block tag doesn't just provide a hole to fill --

   267 it also defines the content that fills the hole in the *parent*. If there were

   268 two similarly-named ``{% block %}`` tags in a template, that template's parent

   269 wouldn't know which one of the blocks' content to use.

   270 

   271 Using the built-in reference

   272 ============================

   273 

   274 Django's admin interface includes a complete reference of all template tags and

   275 filters available for a given site. To see it, go to your admin interface and

   276 click the "Documentation" link in the upper right of the page.

   277 

   278 The reference is divided into 4 sections: tags, filters, models, and views.

   279 

   280 The **tags** and **filters** sections describe all the built-in tags (in fact,

   281 the tag and filter references below come directly from those pages) as well as

   282 any custom tag or filter libraries available.

   283 

   284 The **views** page is the most valuable. Each URL in your site has a separate

   285 entry here, and clicking on a URL will show you:

   286 

   287     * The name of the view function that generates that view.

   288     * A short description of what the view does.

   289     * The **context**, or a list of variables available in the view's template.

   290     * The name of the template or templates that are used for that view.

   291 

   292 Each view documentation page also has a bookmarklet that you can use to jump

   293 from any page to the documentation page for that view.

   294 

   295 Because Django-powered sites usually use database objects, the **models**

   296 section of the documentation page describes each type of object in the system

   297 along with all the fields available on that object.

   298 

   299 Taken together, the documentation pages should tell you every tag, filter,

   300 variable and object available to you in a given template.

   301 

   302 Custom tag and filter libraries

   303 ===============================

   304 

   305 Certain applications provide custom tag and filter libraries. To access them in

   306 a template, use the ``{% load %}`` tag::

   307 

   308     {% load comments %}

   309 

   310     {% comment_form for blogs.entries entry.id with is_public yes %}

   311 

   312 In the above, the ``load`` tag loads the ``comments`` tag library, which then

   313 makes the ``comment_form`` tag available for use. Consult the documentation

   314 area in your admin to find the list of custom libraries in your installation.

   315 

   316 The ``{% load %}`` tag can take multiple library names, separated by spaces.

   317 Example::

   318 

   319     {% load comments i18n %}

   320 

   321 Custom libraries and template inheritance

   322 -----------------------------------------

   323 

   324 When you load a custom tag or filter library, the tags/filters are only made

   325 available to the current template -- not any parent or child templates along

   326 the template-inheritance path.

   327 

   328 For example, if a template ``foo.html`` has ``{% load comments %}``, a child

   329 template (e.g., one that has ``{% extends "foo.html" %}``) will *not* have

   330 access to the comments template tags and filters. The child template is

   331 responsible for its own ``{% load comments %}``.

   332 

   333 This is a feature for the sake of maintainability and sanity.

   334 

   335 Built-in tag and filter reference

   336 =================================

   337 

   338 For those without an admin site available, reference for the stock tags and

   339 filters follows. Because Django is highly customizable, the reference in your

   340 admin should be considered the final word on what tags and filters are

   341 available, and what they do.

   342 

   343 Built-in tag reference

   344 ----------------------

   345 

   346 block

   347 ~~~~~

   348 

   349 Define a block that can be overridden by child templates. See

   350 `Template inheritance`_ for more information.

   351 

   352 comment

   353 ~~~~~~~

   354 

   355 Ignore everything between ``{% comment %}`` and ``{% endcomment %}``

   356 

   357 cycle

   358 ~~~~~

   359 

   360 Cycle among the given strings each time this tag is encountered.

   361 

   362 Within a loop, cycles among the given strings each time through the loop::

   363 

   364     {% for o in some_list %}

   365         <tr class="{% cycle row1,row2 %}">

   366             ...

   367         </tr>

   368     {% endfor %}

   369 

   370 Outside of a loop, give the values a unique name the first time you call it,

   371 then use that name each successive time through::

   372 

   373         <tr class="{% cycle row1,row2,row3 as rowcolors %}">...</tr>

   374         <tr class="{% cycle rowcolors %}">...</tr>

   375         <tr class="{% cycle rowcolors %}">...</tr>

   376 

   377 You can use any number of values, separated by commas. Make sure not to put

   378 spaces between the values -- only commas.

   379 

   380 debug

   381 ~~~~~

   382 

   383 Output a whole load of debugging information, including the current context and

   384 imported modules.

   385 

   386 extends

   387 ~~~~~~~

   388 

   389 Signal that this template extends a parent template.

   390 

   391 This tag can be used in two ways:

   392 

   393    * ``{% extends "base.html" %}`` (with quotes) uses the literal value

   394      ``"base.html"`` as the name of the parent template to extend.

   395 

   396    * ``{% extends variable %}`` uses the value of ``variable``. If the variable

   397      evaluates to a string, Django will use that string as the name of the

   398      parent template. If the variable evaluates to a ``Template`` object,

   399      Django will use that object as the parent template.

   400 

   401 See `Template inheritance`_ for more information.

   402 

   403 filter

   404 ~~~~~~

   405 

   406 Filter the contents of the variable through variable filters.

   407 

   408 Filters can also be piped through each other, and they can have arguments --

   409 just like in variable syntax.

   410 

   411 Sample usage::

   412 

   413     {% filter escape|lower %}

   414         This text will be HTML-escaped, and will appear in all lowercase.

   415     {% endfilter %}

   416 

   417 firstof

   418 ~~~~~~~

   419 

   420 Outputs the first variable passed that is not False.  Outputs nothing if all the

   421 passed variables are False.

   422 

   423 Sample usage::

   424 

   425     {% firstof var1 var2 var3 %}

   426 

   427 This is equivalent to::

   428 

   429     {% if var1 %}

   430         {{ var1 }}

   431     {% else %}{% if var2 %}

   432         {{ var2 }}

   433     {% else %}{% if var3 %}

   434         {{ var3 }}

   435     {% endif %}{% endif %}{% endif %}

   436 

   437 for

   438 ~~~

   439 

   440 Loop over each item in an array.  For example, to display a list of athletes

   441 given ``athlete_list``::

   442 

   443     <ul>

   444     {% for athlete in athlete_list %}

   445         <li>{{ athlete.name }}</li>

   446     {% endfor %}

   447     </ul>

   448 

   449 You can also loop over a list in reverse by using ``{% for obj in list reversed %}``.

   450 

   451 The for loop sets a number of variables available within the loop:

   452 

   453     ==========================  ================================================

   454     Variable                    Description

   455     ==========================  ================================================

   456     ``forloop.counter``         The current iteration of the loop (1-indexed)

   457     ``forloop.counter0``        The current iteration of the loop (0-indexed)

   458     ``forloop.revcounter``      The number of iterations from the end of the

   459                                 loop (1-indexed)

   460     ``forloop.revcounter0``     The number of iterations from the end of the

   461                                 loop (0-indexed)

   462     ``forloop.first``           True if this is the first time through the loop

   463     ``forloop.last``            True if this is the last time through the loop

   464     ``forloop.parentloop``      For nested loops, this is the loop "above" the

   465                                 current one

   466     ==========================  ================================================

   467 

   468 if

   469 ~~

   470 

   471 The ``{% if %}`` tag evaluates a variable, and if that variable is "true" (i.e.

   472 exists, is not empty, and is not a false boolean value) the contents of the

   473 block are output::

   474 

   475     {% if athlete_list %}

   476         Number of athletes: {{ athlete_list|length }}

   477     {% else %}

   478         No athletes.

   479     {% endif %}

   480 

   481 In the above, if ``athlete_list`` is not empty, the number of athletes will be

   482 displayed by the ``{{ athlete_list|length }}`` variable.

   483 

   484 As you can see, the ``if`` tag can take an optional ``{% else %}`` clause that

   485 will be displayed if the test fails.

   486 

   487 ``if`` tags may use ``and``, ``or`` or ``not`` to test a number of variables or

   488 to negate a given variable::

   489 

   490     {% if athlete_list and coach_list %}

   491         Both athletes and coaches are available.

   492     {% endif %}

   493 

   494     {% if not athlete_list %}

   495         There are no athletes.

   496     {% endif %}

   497 

   498     {% if athlete_list or coach_list %}

   499         There are some athletes or some coaches.

   500     {% endif %}

   501 

   502     {% if not athlete_list or coach_list %}

   503         There are no athletes or there are some coaches (OK, so

   504         writing English translations of boolean logic sounds

   505         stupid; it's not our fault).

   506     {% endif %}

   507 

   508     {% if athlete_list and not coach_list %}

   509         There are some athletes and absolutely no coaches.

   510     {% endif %}

   511 

   512 ``if`` tags don't allow ``and`` and ``or`` clauses within the same tag, because

   513 the order of logic would be ambiguous. For example, this is invalid::

   514 

   515     {% if athlete_list and coach_list or cheerleader_list %}

   516 

   517 If you need to combine ``and`` and ``or`` to do advanced logic, just use nested

   518 ``if`` tags. For example::

   519 

   520     {% if athlete_list %}

   521         {% if coach_list or cheerleader_list %}

   522             We have athletes, and either coaches or cheerleaders!

   523         {% endif %}

   524     {% endif %}

   525 

   526 Multiple uses of the same logical operator are fine, as long as you use the

   527 same operator. For example, this is valid::

   528 

   529     {% if athlete_list or coach_list or parent_list or teacher_list %}

   530 

   531 ifchanged

   532 ~~~~~~~~~

   533 

   534 Check if a value has changed from the last iteration of a loop.

   535 

   536 The 'ifchanged' block tag is used within a loop. It has two possible uses.

   537 

   538 1. Checks its own rendered contents against its previous state and only

   539    displays the content if it has changed. For example, this displays a list of

   540    days, only displaying the month if it changes::

   541 

   542         <h1>Archive for {{ year }}</h1>

   543 

   544         {% for date in days %}

   545             {% ifchanged %}<h3>{{ date|date:"F" }}</h3>{% endifchanged %}

   546             <a href="{{ date|date:"M/d"|lower }}/">{{ date|date:"j" }}</a>

   547         {% endfor %}

   548 

   549 2. If given a variable, check whether that variable has changed. For

   550    example, the following shows the date every time it changes, but

   551    only shows the hour if both the hour and the date has changed::

   552 

   553         {% for date in days %}

   554             {% ifchanged date.date %} {{ date.date }} {% endifchanged %}

   555             {% ifchanged date.hour date.date %}

   556                 {{ date.hour }}

   557             {% endifchanged %}

   558         {% endfor %}

   559 

   560 ifequal

   561 ~~~~~~~

   562 

   563 Output the contents of the block if the two arguments equal each other.

   564 

   565 Example::

   566 

   567     {% ifequal user.id comment.user_id %}

   568         ...

   569     {% endifequal %}

   570 

   571 As in the ``{% if %}`` tag, an ``{% else %}`` clause is optional.

   572 

   573 The arguments can be hard-coded strings, so the following is valid::

   574 

   575     {% ifequal user.username "adrian" %}

   576         ...

   577     {% endifequal %}

   578 

   579 It is only possible to compare an argument to template variables or strings.

   580 You cannot check for equality with Python objects such as ``True`` or

   581 ``False``.  If you need to test if something is true or false, use the ``if``

   582 tag instead.

   583 

   584 ifnotequal

   585 ~~~~~~~~~~

   586 

   587 Just like ``ifequal``, except it tests that the two arguments are not equal.

   588 

   589 include

   590 ~~~~~~~

   591 

   592 Loads a template and renders it with the current context. This is a way of

   593 "including" other templates within a template.

   594 

   595 The template name can either be a variable or a hard-coded (quoted) string,

   596 in either single or double quotes.

   597 

   598 This example includes the contents of the template ``"foo/bar.html"``::

   599 

   600     {% include "foo/bar.html" %}

   601 

   602 This example includes the contents of the template whose name is contained in

   603 the variable ``template_name``::

   604 

   605     {% include template_name %}

   606 

   607 An included template is rendered with the context of the template that's

   608 including it. This example produces the output ``"Hello, John"``:

   609 

   610     * Context: variable ``person`` is set to ``"john"``.

   611     * Template::

   612 

   613         {% include "name_snippet.html" %}

   614 

   615     * The ``name_snippet.html`` template::

   616 

   617         Hello, {{ person }}

   618 

   619 See also: ``{% ssi %}``.

   620 

   621 load

   622 ~~~~

   623 

   624 Load a custom template tag set.

   625 

   626 See `Custom tag and filter libraries`_ for more information.

   627 

   628 now

   629 ~~~

   630 

   631 Display the date, formatted according to the given string.

   632 

   633 Uses the same format as PHP's ``date()`` function (http://php.net/date)

   634 with some custom extensions.

   635 

   636 Available format strings:

   637 

   638     ================  ========================================  =====================

   639     Format character  Description                               Example output

   640     ================  ========================================  =====================

   641     a                 ``'a.m.'`` or ``'p.m.'`` (Note that       ``'a.m.'``

   642                       this is slightly different than PHP's

   643                       output, because this includes periods

   644                       to match Associated Press style.)

   645     A                 ``'AM'`` or ``'PM'``.                     ``'AM'``

   646     b                 Month, textual, 3 letters, lowercase.     ``'jan'``

   647     B                 Not implemented.

   648     d                 Day of the month, 2 digits with           ``'01'`` to ``'31'``

   649                       leading zeros.

   650     D                 Day of the week, textual, 3 letters.      ``'Fri'``

   651     f                 Time, in 12-hour hours and minutes,       ``'1'``, ``'1:30'``

   652                       with minutes left off if they're zero.

   653                       Proprietary extension.

   654     F                 Month, textual, long.                     ``'January'``

   655     g                 Hour, 12-hour format without leading      ``'1'`` to ``'12'``

   656                       zeros.

   657     G                 Hour, 24-hour format without leading      ``'0'`` to ``'23'``

   658                       zeros.

   659     h                 Hour, 12-hour format.                     ``'01'`` to ``'12'``

   660     H                 Hour, 24-hour format.                     ``'00'`` to ``'23'``

   661     i                 Minutes.                                  ``'00'`` to ``'59'``

   662     I                 Not implemented.

   663     j                 Day of the month without leading          ``'1'`` to ``'31'``

   664                       zeros.

   665     l                 Day of the week, textual, long.           ``'Friday'``

   666     L                 Boolean for whether it's a leap year.     ``True`` or ``False``

   667     m                 Month, 2 digits with leading zeros.       ``'01'`` to ``'12'``

   668     M                 Month, textual, 3 letters.                ``'Jan'``

   669     n                 Month without leading zeros.              ``'1'`` to ``'12'``

   670     N                 Month abbreviation in Associated Press    ``'Jan.'``, ``'Feb.'``, ``'March'``, ``'May'``

   671                       style. Proprietary extension.

   672     O                 Difference to Greenwich time in hours.    ``'+0200'``

   673     P                 Time, in 12-hour hours, minutes and       ``'1 a.m.'``, ``'1:30 p.m.'``, ``'midnight'``, ``'noon'``, ``'12:30 p.m.'``

   674                       'a.m.'/'p.m.', with minutes left off

   675                       if they're zero and the special-case

   676                       strings 'midnight' and 'noon' if

   677                       appropriate. Proprietary extension.

   678     r                 RFC 822 formatted date.                   ``'Thu, 21 Dec 2000 16:01:07 +0200'``

   679     s                 Seconds, 2 digits with leading zeros.     ``'00'`` to ``'59'``

   680     S                 English ordinal suffix for day of the     ``'st'``, ``'nd'``, ``'rd'`` or ``'th'``

   681                       month, 2 characters.

   682     t                 Number of days in the given month.        ``28`` to ``31``

   683     T                 Time zone of this machine.                ``'EST'``, ``'MDT'``

   684     U                 Not implemented.

   685     w                 Day of the week, digits without           ``'0'`` (Sunday) to ``'6'`` (Saturday)

   686                       leading zeros.

   687     W                 ISO-8601 week number of year, with        ``1``, ``23``

   688                       weeks starting on Monday.

   689     y                 Year, 2 digits.                           ``'99'``

   690     Y                 Year, 4 digits.                           ``'1999'``

   691     z                 Day of the year.                          ``0`` to ``365``

   692     Z                 Time zone offset in seconds. The          ``-43200`` to ``43200``

   693                       offset for timezones west of UTC is

   694                       always negative, and for those east of

   695                       UTC is always positive.

   696     ================  ========================================  =====================

   697 

   698 Example::

   699 

   700     It is {% now "jS F Y H:i" %}

   701 

   702 Note that you can backslash-escape a format string if you want to use the

   703 "raw" value. In this example, "f" is backslash-escaped, because otherwise

   704 "f" is a format string that displays the time. The "o" doesn't need to be

   705 escaped, because it's not a format character.::

   706 

   707     It is the {% now "jS o\f F" %}

   708 

   709 (Displays "It is the 4th of September" %}

   710 

   711 regroup

   712 ~~~~~~~

   713 

   714 Regroup a list of alike objects by a common attribute.

   715 

   716 This complex tag is best illustrated by use of an example:  say that ``people``

   717 is a list of ``Person`` objects that have ``first_name``, ``last_name``, and

   718 ``gender`` attributes, and you'd like to display a list that looks like:

   719 

   720     * Male:

   721         * George Bush

   722         * Bill Clinton

   723     * Female:

   724         * Margaret Thatcher

   725         * Condoleezza Rice

   726     * Unknown:

   727         * Pat Smith

   728 

   729 The following snippet of template code would accomplish this dubious task::

   730 

   731     {% regroup people by gender as grouped %}

   732     <ul>

   733     {% for group in grouped %}

   734         <li>{{ group.grouper }}

   735         <ul>

   736             {% for item in group.list %}

   737             <li>{{ item }}</li>

   738             {% endfor %}

   739         </ul>

   740     {% endfor %}

   741     </ul>

   742 

   743 As you can see, ``{% regroup %}`` populates a variable with a list of objects

   744 with ``grouper`` and ``list`` attributes.  ``grouper`` contains the item that

   745 was grouped by; ``list`` contains the list of objects that share that

   746 ``grouper``.  In this case, ``grouper`` would be ``Male``, ``Female`` and

   747 ``Unknown``, and ``list`` is the list of people with those genders.

   748 

   749 Note that ``{% regroup %}`` does not work when the list to be grouped is not

   750 sorted by the key you are grouping by!  This means that if your list of people

   751 was not sorted by gender, you'd need to make sure it is sorted before using it,

   752 i.e.::

   753 

   754     {% regroup people|dictsort:"gender" by gender as grouped %}

   755 

   756 spaceless

   757 ~~~~~~~~~

   758 

   759 Normalizes whitespace between HTML tags to a single space. This includes tab

   760 characters and newlines.

   761 

   762 Example usage::

   763 

   764     {% spaceless %}

   765         <p>

   766             <a href="foo/">Foo</a>

   767         </p>

   768     {% endspaceless %}

   769 

   770 This example would return this HTML::

   771 

   772     <p> <a href="foo/">Foo</a> </p>

   773 

   774 Only space between *tags* is normalized -- not space between tags and text. In

   775 this example, the space around ``Hello`` won't be stripped::

   776 

   777     {% spaceless %}

   778         <strong>

   779             Hello

   780         </strong>

   781     {% endspaceless %}

   782 

   783 ssi

   784 ~~~

   785 

   786 Output the contents of a given file into the page.

   787 

   788 Like a simple "include" tag, ``{% ssi %}`` includes the contents of another

   789 file -- which must be specified using an absolute path -- in the current

   790 page::

   791 

   792     {% ssi /home/html/ljworld.com/includes/right_generic.html %}

   793 

   794 If the optional "parsed" parameter is given, the contents of the included

   795 file are evaluated as template code, within the current context::

   796 

   797     {% ssi /home/html/ljworld.com/includes/right_generic.html parsed %}

   798 

   799 Note that if you use ``{% ssi %}``, you'll need to define

   800 `ALLOWED_INCLUDE_ROOTS`_ in your Django settings, as a security measure.

   801 

   802 See also: ``{% include %}``.

   803 

   804 .. _ALLOWED_INCLUDE_ROOTS: ../settings/#allowed-include-roots

   805 

   806 templatetag

   807 ~~~~~~~~~~~

   808 

   809 Output one of the syntax characters used to compose template tags.

   810 

   811 Since the template system has no concept of "escaping", to display one of the

   812 bits used in template tags, you must use the ``{% templatetag %}`` tag.

   813 

   814 The argument tells which template bit to output:

   815 

   816     ==================  =======

   817     Argument            Outputs

   818     ==================  =======

   819     ``openblock``       ``{%``

   820     ``closeblock``      ``%}``

   821     ``openvariable``    ``{{``

   822     ``closevariable``   ``}}``

   823     ``openbrace``       ``{``

   824     ``closebrace``      ``}``

   825     ``opencomment``     ``{#``

   826     ``closecomment``    ``#}``

   827     ==================  =======

   828 

   829 url

   830 ~~~

   831 

   832 **Note that the syntax for this tag may change in the future, as we make it more robust.**

   833 

   834 Returns an absolute URL (i.e., a URL without the domain name) matching a given

   835 view function and optional parameters. This is a way to output links without

   836 violating the DRY principle by having to hard-code URLs in your templates::

   837 

   838     {% url path.to.some_view arg1,arg2,name1=value1 %}

   839 

   840 The first argument is a path to a view function in the format

   841 ``package.package.module.function``. Additional arguments are optional and

   842 should be comma-separated values that will be used as positional and keyword

   843 arguments in the URL. All arguments required by the URLconf should be present.

   844 

   845 For example, suppose you have a view, ``app_name.client``, whose URLconf takes

   846 a client ID. The URLconf line might look like this::

   847 

   848     ('^client/(\d+)/$', 'app_name.client')

   849 

   850 If this app's URLconf is included into the project's URLconf under a path

   851 such as this::

   852 

   853     ('^clients/', include('project_name.app_name.urls'))

   854 

   855 ...then, in a template, you can create a link to this view like this::

   856 

   857     {% url app_name.client client.id %}

   858 

   859 The template tag will output the string ``/clients/client/123/``.

   860 

   861 widthratio

   862 ~~~~~~~~~~

   863 

   864 For creating bar charts and such, this tag calculates the ratio of a given value

   865 to a maximum value, and then applies that ratio to a constant.

   866 

   867 For example::

   868 

   869     <img src="bar.gif" height="10" width="{% widthratio this_value max_value 100 %}" />

   870 

   871 Above, if ``this_value`` is 175 and ``max_value`` is 200, the the image in the

   872 above example will be 88 pixels wide (because 175/200 = .875; .875 * 100 = 87.5

   873 which is rounded up to 88).

   874 

   875 Built-in filter reference

   876 -------------------------

   877 

   878 add

   879 ~~~

   880 

   881 Adds the arg to the value.

   882 

   883 addslashes

   884 ~~~~~~~~~~

   885 

   886 Adds slashes. Useful for passing strings to JavaScript, for example.

   887 

   888 

   889 capfirst

   890 ~~~~~~~~

   891 

   892 Capitalizes the first character of the value.

   893 

   894 center

   895 ~~~~~~

   896 

   897 Centers the value in a field of a given width.

   898 

   899 cut

   900 ~~~

   901 

   902 Removes all values of arg from the given string.

   903 

   904 date

   905 ~~~~

   906 

   907 Formats a date according to the given format (same as the ``now`` tag).

   908 

   909 default

   910 ~~~~~~~

   911 

   912 If value is unavailable, use given default.

   913 

   914 default_if_none

   915 ~~~~~~~~~~~~~~~

   916 

   917 If value is ``None``, use given default.

   918 

   919 dictsort

   920 ~~~~~~~~

   921 

   922 Takes a list of dicts, returns that list sorted by the property given in the

   923 argument.

   924 

   925 dictsortreversed

   926 ~~~~~~~~~~~~~~~~

   927 

   928 Takes a list of dicts, returns that list sorted in reverse order by the

   929 property given in the argument.

   930 

   931 divisibleby

   932 ~~~~~~~~~~~

   933 

   934 Returns true if the value is divisible by the argument.

   935 

   936 escape

   937 ~~~~~~

   938 

   939 Escapes a string's HTML. Specifically, it makes these replacements:

   940 

   941     * ``"&"`` to ``"&"``

   942     * ``<`` to ``"&lt;"``

   943     * ``>`` to ``">"``

   944     * ``'"'`` (double quote) to ``'"'``

   945     * ``"'"`` (single quote) to ``'''``

   946 

   947 filesizeformat

   948 ~~~~~~~~~~~~~~

   949 

   950 Format the value like a 'human-readable' file size (i.e. ``'13 KB'``,

   951 ``'4.1 MB'``, ``'102 bytes'``, etc).

   952 

   953 first

   954 ~~~~~

   955 

   956 Returns the first item in a list.

   957 

   958 fix_ampersands

   959 ~~~~~~~~~~~~~~

   960 

   961 Replaces ampersands with ``&`` entities.

   962 

   963 floatformat

   964 ~~~~~~~~~~~

   965 

   966 When used without an argument, rounds a floating-point number to one decimal

   967 place -- but only if there's a decimal part to be displayed. For example:

   968 

   969     * ``36.123`` gets converted to ``36.1``

   970     * ``36.15`` gets converted to ``36.2``

   971     * ``36`` gets converted to ``36``

   972 

   973 If used with a numeric integer argument, ``floatformat`` rounds a number to that 

   974 many decimal places.  For example:

   975 

   976     * ``36.1234`` with floatformat:3 gets converted to ``36.123``

   977     * ``36`` with floatformat:4 gets converted to ``36.0000``

   978 

   979 If the argument passed to ``floatformat`` is negative, it will round a number to

   980 that many decimal places -- but only if there's a decimal part to be displayed.

   981 For example:

   982 

   983     * ``36.1234`` with floatformat:-3 gets converted to ``36.123``

   984     * ``36`` with floatformat:-4 gets converted to ``36``

   985 

   986 Using ``floatformat`` with no argument is equivalent to using ``floatformat`` with 

   987 an argument of ``-1``.

   988 

   989 get_digit

   990 ~~~~~~~~~

   991 

   992 Given a whole number, returns the requested digit of it, where 1 is the

   993 right-most digit, 2 is the second-right-most digit, etc. Returns the original

   994 value for invalid input (if input or argument is not an integer, or if argument

   995 is less than 1). Otherwise, output is always an integer.

   996 

   997 join

   998 ~~~~

   999 

  1000 Joins a list with a string, like Python's ``str.join(list)``.

  1001 

  1002 length

  1003 ~~~~~~

  1004 

  1005 Returns the length of the value. Useful for lists.

  1006 

  1007 length_is

  1008 ~~~~~~~~~

  1009 

  1010 Returns a boolean of whether the value's length is the argument.

  1011 

  1012 linebreaks

  1013 ~~~~~~~~~~

  1014 

  1015 Converts newlines into ``<p>`` and ``<br />`` tags.

  1016 

  1017 linebreaksbr

  1018 ~~~~~~~~~~~~

  1019 

  1020 Converts newlines into ``<br />`` tags.

  1021 

  1022 linenumbers

  1023 ~~~~~~~~~~~

  1024 

  1025 Displays text with line numbers.

  1026 

  1027 ljust

  1028 ~~~~~

  1029 

  1030 Left-aligns the value in a field of a given width.

  1031 

  1032 **Argument:** field size

  1033 

  1034 lower

  1035 ~~~~~

  1036 

  1037 Converts a string into all lowercase.

  1038 

  1039 make_list

  1040 ~~~~~~~~~

  1041 

  1042 Returns the value turned into a list. For an integer, it's a list of

  1043 digits. For a string, it's a list of characters.

  1044 

  1045 phone2numeric

  1046 ~~~~~~~~~~~~~

  1047 

  1048 Converts a phone number (possibly containing letters) to its numerical

  1049 equivalent. For example, ``'800-COLLECT'`` will be converted to

  1050 ``'800-2655328'``.

  1051 

  1052 The input doesn't have to be a valid phone number. This will happily convert

  1053 any string.

  1054 

  1055 pluralize

  1056 ~~~~~~~~~

  1057 

  1058 Returns a plural suffix if the value is not 1. By default, this suffix is ``'s'``.

  1059 

  1060 Example::

  1061 

  1062     You have {{ num_messages }} message{{ num_messages|pluralize }}.

  1063 

  1064 For words that require a suffix other than ``'s'``, you can provide an alternate

  1065 suffix as a parameter to the filter.

  1066 

  1067 Example::

  1068 

  1069     You have {{ num_walruses }} walrus{{ num_walrus|pluralize:"es" }}.

  1070 

  1071 For words that don't pluralize by simple suffix, you can specify both a

  1072 singular and plural suffix, separated by a comma.

  1073 

  1074 Example::

  1075 

  1076     You have {{ num_cherries }} cherr{{ num_cherries|pluralize:"y,ies" }}.

  1077 

  1078 pprint

  1079 ~~~~~~

  1080 

  1081 A wrapper around pprint.pprint -- for debugging, really.

  1082 

  1083 random

  1084 ~~~~~~

  1085 

  1086 Returns a random item from the list.

  1087 

  1088 removetags

  1089 ~~~~~~~~~~

  1090 

  1091 Removes a space separated list of [X]HTML tags from the output.

  1092 

  1093 rjust

  1094 ~~~~~

  1095 

  1096 Right-aligns the value in a field of a given width.

  1097 

  1098 **Argument:** field size

  1099 

  1100 slice

  1101 ~~~~~

  1102 

  1103 Returns a slice of the list.

  1104 

  1105 Uses the same syntax as Python's list slicing. See

  1106 http://diveintopython.org/native_data_types/lists.html#odbchelper.list.slice

  1107 for an introduction.

  1108 

  1109 Example: ``{{ some_list|slice:":2" }}``

  1110 

  1111 slugify

  1112 ~~~~~~~

  1113 

  1114 Converts to lowercase, removes non-word characters (alphanumerics and

  1115 underscores) and converts spaces to hyphens. Also strips leading and trailing

  1116 whitespace.

  1117 

  1118 stringformat

  1119 ~~~~~~~~~~~~

  1120 

  1121 Formats the variable according to the argument, a string formatting specifier.

  1122 This specifier uses Python string formating syntax, with the exception that

  1123 the leading "%" is dropped.

  1124 

  1125 See http://docs.python.org/lib/typesseq-strings.html for documentation of

  1126 Python string formatting

  1127 

  1128 striptags

  1129 ~~~~~~~~~

  1130 

  1131 Strips all [X]HTML tags.

  1132 

  1133 time

  1134 ~~~~

  1135 

  1136 Formats a time according to the given format (same as the ``now`` tag).