jinja2.filters

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Pass the context as the first argument to the decorated function.

Get an attribute of an object. foo|attr("bar") works like foo.bar just that always an attribute is returned and items are not looked up.

See :ref:`Notes on subscriptions <notes-on-subscriptions>` for more details.

A filter that batches items. It works pretty much like slice just the other way round. It returns a list of lists with the given number of items. If you provide a second parameter this is used to fill up missing items. See this example:

<table>
{%- for row in items|batch(3, '&nbsp;') %}
  <tr>
  {%- for column in row %}
    <td>{{ column }}</td>
  {%- endfor %}
  </tr>
{%- endfor %}
</table>

If the value is undefined it will return the passed default value, otherwise the value of the variable:

{{ my_variable|default('my_variable is not defined') }}

This will output the value of my_variable if the variable was defined, otherwise 'my_variable is not defined'. If you want to use default with variables that evaluate to false you have to set the second parameter to true:

{{ ''|default('the string was empty', true) }}

Sort a dict and yield (key, value) pairs. Python dicts may not be in the order you want to display them in, so sort them first.

{% for key, value in mydict|dictsort %}
    sort the dict by key, case insensitive

{% for key, value in mydict|dictsort(reverse=true) %}
    sort the dict by key, case insensitive, reverse order

{% for key, value in mydict|dictsort(true) %}
    sort the dict by key, case sensitive

{% for key, value in mydict|dictsort(false, 'value') %}
    sort the dict by value, case insensitive

Undocumented

Apply the given values to a printf-style format string, like string % values.

{{ "%s, %s!"|format(greeting, name) }}
Hello, World!

In most cases it should be more convenient and efficient to use the % operator or str.format.

{{ "%s, %s!" % (greeting, name) }}
{{ "{}, {}!".format(greeting, name) }}

Undocumented

Return a copy of the string with each line indented by 4 spaces. The first line and blank lines are not indented by default.

Undocumented

Return the last item of a sequence.

Note: Does not work with generators. You may want to explicitly convert it to a list:

{{ data | selectattr('name', '==', 'Jinja') | list | last }}

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Return the largest item from the sequence.

{{ [1, 2, 3]|max }}
    -> 3

Return the smallest item from the sequence.

{{ [1, 2, 3]|min }}
    -> 1

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Return a copy of the value with all occurrences of a substring replaced with a new one. The first argument is the substring that should be replaced, the second is the replacement string. If the optional third argument count is given, only the first count occurrences are replaced:

{{ "Hello World"|replace("Hello", "Goodbye") }}
    -> Goodbye World

{{ "aaaaargh"|replace("a", "d'oh, ", 2) }}
    -> d'oh, d'oh, aaargh

Round the number to a given precision. The first parameter specifies the precision (default is 0), the second the rounding method:

• 'common' rounds either up or down
• 'ceil' always rounds up
• 'floor' always rounds down

If you don't specify a method 'common' is used.

{{ 42.55|round }}
    -> 43.0
{{ 42.55|round(1, 'floor') }}
    -> 42.5

Note that even if rounded to 0 precision, a float is returned. If you need a real integer, pipe it through int:

{{ 42.55|round|int }}
    -> 43

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Sort an iterable using Python's sorted.

{% for city in cities|sort %}
    ...
{% endfor %}

The sort is stable, it does not change the relative order of elements that compare equal. This makes it is possible to chain sorts on different attributes and ordering.

{% for user in users|sort(attribute="name")
    |sort(reverse=true, attribute="age") %}
    ...
{% endfor %}

As a shortcut to chaining when the direction is the same for all attributes, pass a comma separate list of attributes.

{% for user users|sort(attribute="age,name") %}
    ...
{% endfor %}

Undocumented

Serialize an object to a string of JSON, and mark it safe to render in HTML. This filter is only for use in HTML documents.

The returned string is safe to render in HTML documents and <script> tags. The exception is in HTML attributes that are double quoted; either use single quotes or the |forceescape filter.

Return a truncated copy of the string. The length is specified with the first parameter which defaults to 255. If the second parameter is true the filter will cut the text at length. Otherwise it will discard the last word. If the text was in fact truncated it will append an ellipsis sign ("..."). If you want a different ellipsis sign than "..." you can specify it using the third parameter. Strings that only exceed the length by the tolerance margin given in the fourth parameter will not be truncated.

{{ "foo bar baz qux"|truncate(9) }}
    -> "foo..."
{{ "foo bar baz qux"|truncate(9, True) }}
    -> "foo ba..."
{{ "foo bar baz qux"|truncate(11) }}
    -> "foo bar baz qux"
{{ "foo bar baz qux"|truncate(11, False, '...', 0) }}
    -> "foo bar..."

The default leeway on newer Jinja versions is 5 and was 0 before but can be reconfigured globally.

Returns a list of unique items from the given iterable.

{{ ['foo', 'bar', 'foobar', 'FooBar']|unique|list }}
    -> ['foo', 'bar', 'foobar']

The unique items are yielded in the same order as their first occurrence in the iterable passed to the filter.

Quote data for use in a URL path or query using UTF-8.

Basic wrapper around urllib.parse.quote when given a string, or urllib.parse.urlencode for a dict or iterable.

When given a string, "/" is not quoted. HTTP servers treat "/" and "%2F" equivalently in paths. If you need quoted slashes, use the |replace("/", "%2F") filter.

Convert URLs in text into clickable links.

This may not recognize links in some situations. Usually, a more comprehensive formatter, such as a Markdown library, is a better choice.

Works on http://, https://, www., mailto:, and email addresses. Links with trailing punctuation (periods, commas, closing parentheses) and leading punctuation (opening parentheses) are recognized excluding the punctuation. Email addresses that include header fields are not recognized (for example, mailto:address@example.com?cc=copy@example.com).

Wrap a string to the given width. Existing newlines are treated as paragraphs to be wrapped separately.

Create an SGML/XML attribute string based on the items in a dict. All values that are neither none nor undefined are automatically escaped:

<ul{{ {'class': 'my_list', 'missing': none,
        'id': 'list-%d'|format(variable)}|xmlattr }}>
...
</ul>

Results in something like this:

<ul class="my_list" id="list-42">
...
</ul>

As you can see it automatically prepends a space in front of the item if the filter returned something unless the second parameter is false.

Pass the environment as the first argument to the decorated function.

Pass the eval context as the first argument to the decorated function.

Returns a callable that looks up the given comma separated attributes from a passed object with the rules of the environment. Dots are allowed to access attributes of each attribute. Integer parts in paths are looked up as integers.

The value returned by the returned callable is a list of extracted attribute values.

Examples of attribute: "attr1,attr2", "attr1.inner1.0,attr2.inner2.0", etc.

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Group a sequence of objects by an attribute using Python's itertools.groupby. The attribute can use dot notation for nested access, like "address.city". Unlike Python's groupby, the values are sorted first so only one group is returned for each unique value.

For example, a list of User objects with a city attribute can be rendered in groups. In this example, grouper refers to the city value of the group.

<ul>{% for city, items in users|groupby("city") %}
  <li>{{ city }}
    <ul>{% for user in items %}
      <li>{{ user.name }}
    {% endfor %}</ul>
  </li>
{% endfor %}</ul>

groupby yields namedtuples of (grouper, list), which can be used instead of the tuple unpacking above. grouper is the value of the attribute, and list is the items with that value.

<ul>{% for group in users|groupby("city") %}
  <li>{{ group.grouper }}: {{ group.list|join(", ") }}
{% endfor %}</ul>

You can specify a default value to use if an object in the list does not have the given attribute.

<ul>{% for city, items in users|groupby("city", default="NY") %}
  <li>{{ city }}: {{ items|map(attribute="name")|join(", ") }}</li>
{% endfor %}</ul>

Return a string which is the concatenation of the strings in the sequence. The separator between elements is an empty string per default, you can define it with the optional parameter:

{{ [1, 2, 3]|join('|') }}
    -> 1|2|3

{{ [1, 2, 3]|join }}
    -> 123

It is also possible to join certain attributes of an object:

{{ users|join(', ', attribute='username') }}

Applies a filter on a sequence of objects or looks up an attribute. This is useful when dealing with lists of objects but you are really only interested in a certain value of it.

The basic usage is mapping on an attribute. Imagine you have a list of users but you are only interested in a list of usernames:

Users on this page: {{ users|map(attribute='username')|join(', ') }}

You can specify a default value to use if an object in the list does not have the given attribute.

{{ users|map(attribute="username", default="Anonymous")|join(", ") }}

Alternatively you can let it invoke a filter by passing the name of the filter and the arguments afterwards. A good example would be applying a text conversion filter on a sequence:

Users on this page: {{ titles|map('lower')|join(', ') }}

Similar to a generator comprehension such as:

(u.username for u in users)
(getattr(u, "username", "Anonymous") for u in users)
(do_lower(x) for x in titles)

Filters a sequence of objects by applying a test to each object, and rejecting the objects with the test succeeding.

If no test is specified, each object will be evaluated as a boolean.

Example usage:

{{ numbers|reject("odd") }}

Similar to a generator comprehension such as:

(n for n in numbers if not test_odd(n))

Filters a sequence of objects by applying a test to the specified attribute of each object, and rejecting the objects with the test succeeding.

If no test is specified, the attribute's value will be evaluated as a boolean.

{{ users|rejectattr("is_active") }}
{{ users|rejectattr("email", "none") }}

Similar to a generator comprehension such as:

(u for user in users if not user.is_active)
(u for user in users if not test_none(user.email))

Filters a sequence of objects by applying a test to each object, and only selecting the objects with the test succeeding.

If no test is specified, each object will be evaluated as a boolean.

Example usage:

{{ numbers|select("odd") }}
{{ numbers|select("odd") }}
{{ numbers|select("divisibleby", 3) }}
{{ numbers|select("lessthan", 42) }}
{{ strings|select("equalto", "mystring") }}

Similar to a generator comprehension such as:

(n for n in numbers if test_odd(n))
(n for n in numbers if test_divisibleby(n, 3))

Filters a sequence of objects by applying a test to the specified attribute of each object, and only selecting the objects with the test succeeding.

If no test is specified, the attribute's value will be evaluated as a boolean.

Example usage:

{{ users|selectattr("is_active") }}
{{ users|selectattr("email", "none") }}

Similar to a generator comprehension such as:

(u for user in users if user.is_active)
(u for user in users if test_none(user.email))

Slice an iterator and return a list of lists containing those items. Useful if you want to create a div containing three ul tags that represent columns:

<div class="columnwrapper">
  {%- for column in items|slice(3) %}
    <ul class="column-{{ loop.index }}">
    {%- for item in column %}
      <li>{{ item }}</li>
    {%- endfor %}
    </ul>
  {%- endfor %}
</div>

If you pass it a second argument it's used to fill missing values on the last iteration.

Returns the sum of a sequence of numbers plus the value of parameter 'start' (which defaults to 0). When the sequence is empty it returns start.

It is also possible to sum up only certain attributes:

Total: {{ items|sum(attribute='price') }}