for

Loop over each item in a sequence. For example, to display a list of users provided in a variable called users:

<h1>Members</h1>
<ul>
    {% for user in users %}
        <li>{{ user.username|e }}</li>
    {% endfor %}
</ul>

If you do need to iterate over a sequence of numbers, you can use the .. operator:

{% for i in 0..10 %}
    * {{ i }}
{% endfor %}

The above snippet of code would print all numbers from 0 to 10.

It can be also useful with letters:

{% for letter in 'a'..'z' %}
    * {{ letter }}
{% endfor %}

The .. operator can take any expression at both sides:

{% for letter in 'a'|upper..'z'|upper %}
    * {{ letter }}
{% endfor %}

The loop variable

Inside of a for loop block you can access some special variables:

{% for user in users %}
{{ loop.index }} - {{ user.username }}
{% endfor %}

The else Clause

If no iteration took place because the sequence was empty, you can render a replacement block by using else:

<ul>
    {% for user in users %}
        <li>{{ user.username|e }}</li>
    {% else %}
        <li><em>no user found</em></li>
    {% endfor %}
</ul>

Iterating over Keys

By default, a loop iterates over the values of the sequence. You can iterate on keys by using the keys filter:

<h1>Members</h1>
<ul>
    {% for key in users|keys %}
        <li>{{ key }}</li>
    {% endfor %}
</ul>

Iterating over Keys and Values

You can also access both keys and values:

<h1>Members</h1>
<ul>
    {% for key, user in users %}
        <li>{{ key }}: {{ user.username|e }}</li>
    {% endfor %}
</ul>

Iterating over a Subset

You might want to iterate over a subset of values. This can be achieved using the slice filter:

<h1>Top Ten Members</h1>
<ul>
    {% for user in users|slice(0, 10) %}
        <li>{{ user.username|e }}</li>
    {% endfor %}
</ul>