Filters & Functions

Filters

Variables can be modified by filters. Filters are separated from the variable by a pipe symbol (|). Multiple filters can be chained. The output of one filter is applied to the next.

The following example removes all HTML tags from the name and title-cases it:

{{ name | striptags | title }}

Filters that accept arguments have parentheses around the arguments. This example joins the elements of a list by commas:

{{ list | join(', ') }}

To apply a filter on a section of code, wrap it with the apply tag:

{% apply upper %}
  This text becomes uppercase
{% endapply %}

Functions

Functions can be called to generate content. Functions are called by their name followed by parentheses (()) and may have arguments.

For instance, the range function returns a list containing an arithmetic progression of integers:

{% for i in range(0, 3) %}
  {{ i }},
{% endfor %}

Named arguments

{% for i in range(low = 1, high = 10, step = 2) %}
  {{ i }},
{% endfor %}

Using named arguments makes your templates more explicit about the meaning of the values you pass as arguments:

{{ data | convert_encoding('UTF-8', 'iso-2022-jp') }}

{# versus #}

{{ data | convert_encoding(from = 'iso-2022-jp', to = 'UTF-8') }}

Named arguments also allow you to skip some arguments for which you don't want to change the default value:

{# the first argument is the date format, which defaults to the global date format if null is passed #}
{{ 'now' | date(null, 'Europe/Paris') }}

{# or skip the format value by using a named argument for the time zone #}
{{ 'now' | date(timezone = 'Europe/Paris') }}

You can also use both positional and named arguments in one call, in which case positional arguments must always come before named arguments:

{{ 'now' | date('d/m/Y H:i', timezone = 'Europe/Paris') }}

Each function and filter documentation page has a section where the names of all arguments are listed when supported.