for
Loop over each item in a sequence. For example, to display a list of users
provided in a variable called users
:
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<h1>Members</h1>
<ul>
{% for user in users %}
<li>{{ user.username|e }}</li>
{% endfor %}
</ul>
Note
A sequence can be either an array or an object implementing the
Traversable
interface.
If you do need to iterate over a sequence of numbers, you can use the ..
operator:
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{% 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:
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{% for letter in 'a'..'z' %}
* {{ letter }}
{% endfor %}
The ..
operator can take any expression at both sides:
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{% for letter in 'a'|upper..'z'|upper %}
* {{ letter }}
{% endfor %}
If you need a step different from 1, you can use the
range
function instead.
The `loop` variable
Inside of a for
loop block you can access some special variables:
Variable | Description |
---|---|
loop.index |
The current iteration of the loop. (1 indexed) |
loop.index0 |
The current iteration of the loop. (0 indexed) |
loop.revindex |
The number of iterations from the end of the loop (1 indexed) |
loop.revindex0 |
The number of iterations from the end of the loop (0 indexed) |
loop.first |
True if first iteration |
loop.last |
True if last iteration |
loop.length |
The number of items in the sequence |
loop.parent |
The parent context |
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{% for user in users %}
{{ loop.index }} - {{ user.username }}
{% endfor %}
Note
The loop.length
, loop.revindex
, loop.revindex0
, and
loop.last
variables are only available for PHP arrays, or objects that
implement the Countable
interface.
The `else` Clause
If no iteration took place because the sequence was empty, you can render a
replacement block by using else
:
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<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:
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<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:
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<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:
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<h1>Top Ten Members</h1>
<ul>
{% for user in users|slice(0, 10) %}
<li>{{ user.username|e }}</li>
{% endfor %}
</ul>