Twig Components / Methods / set

set is a Twig tag to assign values to variables inside code blocks. Assignments use the set tag and can have multiple targets.

Here is how you can assign the bar value to the foo variable:

{% set foo = 'bar' %}

After the set call, the foo variable is available in the template like any other ones:

{# displays bar #}
{{ foo }}

The assigned value can be any valid Twig expression:

{% set foo = [1, 2] %}
{% set foo = {'foo': 'bar'} %}
{% set foo = 'foo' ~ 'bar' %}

Several variables can be assigned in one block:

{% set foo, bar = 'foo', 'bar' %}

{# is equivalent to #}

{% set foo = 'foo' %}
{% set bar = 'bar' %}

The set tag can also be used to 'capture' chunks of text:

{% set foo %}
     <div id="pagination">
        ...
    </div>
{% endset %}

Caution: If you enable automatic output escaping, Twig will only consider the content to be safe when capturing chunks of text.

Note: Note that loops are scoped in Twig; therefore a variable declared inside a for loop is not accessible outside the loop itself:

{% for item in list %}
    {% set foo = item %}
{% endfor %}

{# foo is NOT available #}

If you want to access the variable, just declare it before the loop:

{% set foo = "" %}
{% for item in list %}
    {% set foo = item %}
{% endfor %}

{# foo is available #}

Source: Twig