{% if %}
The {% if %}
and {% endif %}
tags will represent an expression and is comparable with the if statements of PHP. In the simplest form you can use it to test if an expression evaluates to true
:
{% if online == false %}
<p>The website is in maintenance mode.</p>
{% endif %}
You can also test if an array is not empty:
{% if users %}
<ul>
{% for user in users %}
<li>{{ user.username }}</li>
{% endfor %}
</ul>
{% endif %}
Note: If you want to test if the variable is defined, use
{% if users is defined %}
instead.
You can also use not
to check for values that evaluate to false
:
{% if not user.subscribed %}
<p>You are not subscribed to our mailing list.</p>
{% endif %}
For multiple expressions {% elseif %}
and {% else %}
can be used:
{% if kenny.sick %}
Kenny is sick.
{% elseif kenny.dead %}
You killed Kenny! You bastard!!!
{% else %}
Kenny looks okay so far.
{% endif %}
# Expression rules
The rules to determine if an expression is true or false are the same as in PHP, here are the edge cases rules:
Value | Boolean evaluation |
---|---|
empty string | false |
numeric zero | false |
whitespace-only string | true |
empty array | false |
null | false |
non-empty array | true |
object | true |