The {% for %} and {% endfor %} tags will loop over each value in a collection. A collection can be either an array or an object implementing the Traversable interface.

<ul>
    {% for user in users %}
        <li>{{ user.username }}</li>
    {% endfor %}
</ul>

You can also access both keys and values:

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

If the collection is empty, you can render a replacement block by using else:

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

Looping a collection

If you do need to iterate over a collection 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 also be 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 %}

Adding a condition

Unlike in PHP there is no function to break or continue in a loop, however you can still filter the collection. The following example skips all the users which are not active:

<ul>
    {% for user in users if user.active %}
        <li>{{ user.username }}</li>
    {% endfor %}
</ul>

The loop variable

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

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