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Posted on 2006-11-30 22:15 pts 阅读(2438) 评论(0) 编辑 收藏 所属分类: Django
The Django template language: For template authors
This covers Django version 0.95 and the development version. Old docs: 0.90, 0.91
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.
Django的模板语言力求在易用和功能之间达到平衡，如果用户熟悉HTML语言，则使用起来会很舒服，如果你有其他文本式的模板语言使用经验，如Smarty、CheetahTemplate，在使用Django模板时你也会感觉非常熟悉。
Templates
A template is simply a text file. It can generate any text-based format (HTML, XML, CSV, etc.).
一个简单的文本格式文件就是一个模板，它可以是html、xml、csv等各种文本格式。
A template contains variables, which get replaced with values when the template is evaluated, and tags, which control the logic of the template.
模板文件包括变量，标签。变量在模板执行时被替换为实际值，标签用力控制模板执行逻辑。
Below is a minimal template that illustrates a few basics. Each element will be explained later in this document.:
下面是一个简单的基本模板元素应用示例，各元素意义将在后面陆续讲解。
{% extends "base_generic.html" %}
{% block title %}{{ section.title }}{% endblock %}
{% block content %}
<h1>{{ section.title }}</h1>
{% for story in story_list %}
<h2>
<a href="{{ story.get_absolute_url }}">
{{ story.headline|upper }}
</a>
</h2>
<p>{{ story.tease|truncatewords:"100" }}</p>
{% endfor %}
{% endblock %}
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!
为什么使用文本格式而不是xml格式，比如Zope的TAL？因为我们希望Django模板语言不仅仅适用XML/HTML，我们还希望它可适用于Email、js教本、csv，可以是任何文本格式。还有一点，编辑XML有点不人道。
Variables
变量
Variables look like this: {{ variable }}. When the template engine encounters a variable, it evaluates that variable and replaces it with the result.
变量使用格式是{{变量名}}。但模板解释器遇到它时，就会用变量的实际值来替换。
Use a dot (.) to access attributes of a variable.
可以使用逗点"."获取变量属性。
Behind the scenes
实现细节
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
在技术上，但模板解释器遇到逗点操作符时，他会按照一下顺序查找属性值：
In the above example, {{ section.title }} will be replaced with the title attribute of the section object.
在上面的例子中，{{section.title}}会被section对象的title属性值替换掉。
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.
如果一个变量不存在，解释器会插入设置文件中TEMPLATE_STRING_IF_INVALID的值，默认是空字符串。
See Using the built-in reference, below, for help on finding what variables are available in a given template.
Filters
过滤器
You can modify variables for display by using filters.
你可以使用过滤器来改变变量值的最终显示结果。
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.
过滤器的形式为：{{name|lower}},它将对变量name施用过滤器lower，即将name值全部小写。"|"表示应用过滤器。
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 <p> tags.
过滤器可以嵌套，前一个输出可以作为下一个过滤器的输入。比如{{text|escape|linebreaks}}
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 always are in double quotes.
有些过滤器可以有参数，如{{bio|truncatewords:"30"}}，它将仅显示bio变量值的前30个字符，参数通常使用双引号。
The Built-in filter reference below describes all the built-in filters.
Template inheritance
模板继承
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.
继承是Django模板应用中一项功能强大、使用最复杂的一项机制，模板继承可以让你先建立一个基础架构模板，包含你站点中的所有公共元素，个性元素可以定义为blocks块，供子模板去继承。
It's easiest to understand template inheritance by starting with an example:
下面就让我们从最简单的模板扩展例子开始：
<!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" xml:lang="en" lang="en">
<head>
<link rel="stylesheet" href="style.css" />
<title>{% block title %}My amazing site{% endblock %}</title>
</head>
<body>
<div id="sidebar">
{% block sidebar %}
<ul>
<li><a href="/">Home</a></li>
<li><a href="/blog/">Blog</a></li>
</ul>
{% endblock %}
</div>
<div id="content">
{% block content %}{% endblock %}
</div>
</body>
</html>
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.
这个模板文件我们保存为base.html，它定义了一个基本的文档框架，包含两个列项，子模板的任务就是填充需要自定义的项。
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.
在例子中，{% block %}标签定义了需要子模板填充的项，block标签就是要告诉模板解释器，这些内容是需要子模板自定义的项目。
A child template might look like this:
一个子模板可能看起来像这样：
{% extends "base.html" %}
{% block title %}My amazing blog{% endblock %}
{% block content %}
{% for entry in blog_entries %}
<h2>{{ entry.title }}</h2>
<p>{{ entry.body }}</p>
{% 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".
{% extends %}标签在这里很重要，它告诉解释器这个模板文件继承自另外一个模板，当模板解释器碰到这个标签时，它会首先定位父模板，即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:
在这种情况下，解释器会用子模板中定义的block内容替换掉父模板中的相应的内容。根据对象blog_entries具体内容，子模板输出的内容可能像下面这样：
<!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" xml:lang="en" lang="en">
<head>
<link rel="stylesheet" href="style.css" />
<title>My amazing blog</title>
</head>
<body>
<div id="sidebar">
<ul>
<li><a href="/">Home</a></li>
<li><a href="/blog/">Blog</a></li>
</ul>
</div>
<div id="content">
<h2>Entry one</h2>
<p>This is my first entry.</p>
<h2>Entry two</h2>
<p>This is my second entry.</p>
</div>
</body>
</html>
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.
请注意，尽管子模板中没有定义sidebar块，但解释器自动将父模板的sidebar块内容继承下来。父模板中block块的内容总是作为所有子模板中的缺省内容。
You can use as many levels of inheritance as needed. One common way of using inheritance is the following three-level approach:
你可以使用你需要的任意层次的继承层次。通常的继承用法需要下面的三个步骤：
- Create a base.html template that holds the main look-and-feel of your site. 创建一个base.html文件，包括你站点的主要元素
- 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. 为每种不同需要建立单独的子模板文件，如base_news.html、base_sports.html，他们继承自base.html，包含有特别的样式和内容。
- 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. {% extends %}
- 标签必须是模板文件中的第一个标签。
- 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.
- 尽量多在base模板文件中定义block块，子模板不必全部重定义父模板中的每一个block块。
- 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.
- 如果你发现有重复定义的内容，那就意味着你也许要将重复的项目定义为父模板中的一个block块。
- 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.
- 如果需要引用父模板中的block块，可以使用block.super变量，特别是在你需要增加父标签内容而不是覆盖父标签内容时。
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.
最后，需要注意几点：一个模板文件中不能有多个相同的block标签变量名。
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.
Django模板内置四种引用类型：tags,filters,models,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标签后可跟多个库名，用空格格开，如：
{% 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.
引入的标签库仅对当前模板文件有效。
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
内置的几种标签：
block
Define a block that can be overridden by child templates. See Template inheritance for more information.
定义可继承的block块。
cycle
Cycle among the given strings each time this tag is encountered.
？？？？？？
Within a loop, cycles among the given strings each time through the loop:
{% for o in some_list %}
<tr class="{% cycle row1,row2 %}">
...
</tr>
{% 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:
<tr class="{% cycle row1,row2,row3 as rowcolors %}">...</tr>
<tr class="{% cycle rowcolors %}">...</tr>
<tr class="{% cycle rowcolors %}">...</tr>
You can use any number of values, separated by commas. Make sure not to put spaces between the values -- only commas.
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标签可以有两种用法：
- {% extends "base.html" %} (with quotes) uses the literal value "base.html" as the name of the parent template to extend.
- 继承自某个模板文件，后跟文件名
- {% 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.
- 继承自某个模板文件，后跟变量名
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.
输出第一个True值。如果全为False，什么也不输出。
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 given athlete_list:
<ul>
{% for athlete in athlete_list %}
<li>{{ athlete.name }}</li>
{% endfor %}
</ul>
You can also loop over a list in reverse by using {% for obj in list reversed %}.
可以用反序循环：{% for obj in list reversed %}
The for loop sets a number of variables available within the loop:
| Variable |
Description |
| forloop.counter |
The current iteration of the loop (1-indexed)当前循环次数 1开始 |
| forloop.counter0 |
The current iteration of the loop (0-indexed)当前循环次数 0开始 |
| forloop.revcounter |
The number of iterations from the end of the loop (1-indexed)循环剩余次数，1开始 |
| forloop.revcounter0 |
The number of iterations from the end of the loop (0-indexed)循环剩余次数，1开始
|
| forloop.first |
True if this is the first time through the loop，如果是第一次循环则为真 |
| forloop.last |
True if this is the last time through the loop，如果是组后一次循环则为真 |
| 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标签不允许同时使用and 和 or 语句，如果确实需要，可以使用嵌套的if语句。
{% 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.
检查在循环中变量的值或某属性是否改变，如改变，则输出相应内容。
The 'ifchanged' block tag is used within a loop. It has two possible uses.
-
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:
<h1>Archive for {{ year }}</h1>
{% for date in days %}
{% ifchanged %}<h3>{{ date|date:"F" }}</h3>{% endifchanged %}
<a href="{{ date|date:"M/d"|lower }}/">{{ date|date:"j" }}</a>
{% endfor %}
-
New in Django development version. 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.
如果两个变量内容相同，输出相应内容。
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.
不能使用ifequal比较python对象，如true、false，如果需要，可以使用if标签。
ifnotequal
Just like ifequal, except it tests that the two arguments are not equal.
如果不相等，基本同ifequal。
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 %}.
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 this is slightly different than PHP's output, because this includes periods to match Associated Press style.) |
'a.m.' |
| A |
'AM' or 'PM'. |
'AM' |
| B |
Not implemented. |
|
| d |
Day of the month, 2 digits with leading zeros. |
'01' to '31' |
| D |
Day of the week, textual, 3 letters. |
'Fri' |
| f |
Time, in 12-hour hours and minutes, with minutes left off if they're zero. Proprietary extension. |
'1', '1:30' |
| F |
Month, textual, long. |
'January' |
| g |
Hour, 12-hour format without leading zeros. |
'1' to '12' |
| G |
Hour, 24-hour format without leading zeros. |
'0' to '23' |
| 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 zeros. |
'1' to '31' |
| 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 style. Proprietary extension. |
'Jan.', 'Feb.', 'March', 'May' |
| O |
Difference to Greenwich time in hours. |
'+0200' |
| P |
Time, in 12-hour hours, minutes and 'a.m.'/'p.m.', with minutes left off if they're zero and the special-case strings 'midnight' and 'noon' if appropriate. Proprietary extension. |
'1 a.m.', '1:30 p.m.', 'midnight', 'noon', '12:30 p.m.' |
| 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 month, 2 characters. |
'st', 'nd', 'rd' or 'th' |
| 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 leading zeros. |
'0' (Sunday) to '6' (Saturday) |
| W |
ISO-8601 week number of year, with weeks starting on Monday. |
1, 23 |
| 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 offset for timezones west of UTC is always negative, and for those east of UTC is always positive. |
-43200 to 43200 |
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" %}
(Displays "It is the 4th of September" %}
regroup
Regroup a list of alike objects by a common attribute.
！使用一个属性来对list分组。
This complex tag is best illustrated by use of an example: say that people is a list of Person objects that have first_name, last_name, and gender attributes, and you'd like to display a list that looks like:
-
- Male:
-
-
- Female:
-
- Margaret Thatcher
- Condoleezza Rice
-
- Unknown:
-
The following snippet of template code would accomplish this dubious task:
{% regroup people by gender as grouped %}
<ul>
{% for group in grouped %}
<li>{{ group.grouper }}
<ul>
{% for item in group.list %}
<li>{{ item }}</li>
{% endfor %}
</ul>
{% endfor %}
</ul>
As you can see, {% regroup %} populates a variable with a list of objects with grouper and list attributes. grouper contains the item that was grouped by; list contains the list of objects that share that grouper. In this case, grouper would be Male, Female and Unknown, and list is the list of people with those genders.
Note that {% regroup %} does not work when the list to be grouped is not sorted by the key you are grouping by! This means that if your list of people was not sorted by gender, you'd need to make sure it is sorted before using it, i.e.:
{% regroup people|dictsort:"gender" by gender as grouped %}
spaceless
Normalizes whitespace between HTML tags to a single space. This includes tab characters and newlines.
Example usage:
{% spaceless %}
<p>
<a href="foo/">Foo</a>
</p>
{% endspaceless %}
This example would return this HTML:
<p> <a href="foo/">Foo</a> </p>
Only space between tags is normalized -- not space between tags and text. In this example, the space around Hello won't be stripped:
只对标签之间的空格有效，对标签和文本之间的空格无效。如下面Hello前后的空格不会被格式化。
{% spaceless %}
<strong>
Hello
</strong>
{% endspaceless %}
ssi
Output the contents of a given file into the page.
引入一个给定文件的内容。
Like a simple "include" tag, {% ssi %} includes the contents of another file -- which must be specified using an absolute path -- in the current page:
必须使用一个绝对路径：
{% 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:
如果parsed参数被应用，引用的文件被看作是一个模板文件：
{% 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.
要使用ssi标签，需要在setting文件中设定ALLOWED_INCLUDE_ROOTS的值。
See also: {% include %}.
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 |
#} |
Note: opencomment and closecomment are new in the Django development version.
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.
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For example:
<img src="bar.gif" height="10" width="{% widthratio this_value max_value 100 %}" />
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).
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 dicts, returns that list sorted by the property given in the argument.
dictsortreversed
Takes a list of dicts, returns that list sorted in reverse order by the property given in the argument.
divisibleby
Returns true if the value is divisible by the argument.
escape
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Escapes a string's HTML. Specifically, it makes these replacements:
- "&" to "&"
- < to "<"
- > to ">"
- '"' (double quote) to '"'
- "'" (single quote) to '''
first
Returns the first item in a list.
fix_ampersands
Replaces ampersands with & entities.
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.
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 <p> and <br /> tags.
linebreaksbr
Converts newlines into <br /> 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.
rjust
Right-aligns the value in a field of a given width.
Argument: field size
slugify
Converts to lowercase, removes non-word characters (alphanumerics and underscores) and converts spaces to hyphens. Also strips leading and trailing whitespace.
time
Formats a time according to the given format (same as the now tag).
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
unordered_list
Recursively takes a self-nested list and returns an HTML unordered list -- WITHOUT opening and closing <ul> tags.
The list is assumed to be in the proper format. For example, if var contains ['States', [['Kansas', [['Lawrence', []], ['Topeka', []]]], ['Illinois', []]]], then {{ var|unordered_list }} would return:
<li>States
<ul>
<li>Kansas
<ul>
<li>Lawrence</li>
<li>Topeka</li>
</ul>
</li>
<li>Illinois</li>
</ul>
</li>
upper
Converts a string into all uppercase.
urlencode
Escapes a value for use in a URL.
urlize
Converts URLs in plain text into clickable links.
将文本中的url转换为可点击的链接。
urlizetrunc
Converts URLs into clickable links, truncating URLs to the given character limit.
Argument: Length to truncate URLs to
wordcount
Returns the number of words.
wordwrap
Wraps words at specified line length.
Argument: number of characters at which to wrap the text
yesno
Given a string mapping values for true, false and (optionally) None, returns one of those strings according to the value:
| Value |
Argument |
Outputs |
| True |
"yeah,no,maybe" |
yeah |
| False |
"yeah,no,maybe" |
no |
| None |
"yeah,no,maybe" |
maybe |
| None |
"yeah,no" |
"no" (converts None to False if no mapping for None is given) |
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