if
#
The if
statement in Twig 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>Our website is in maintenance mode. Please, come back later.</p>
{% endif %}
You can also test if an array is not empty:
{% if users %}
<ul>
{% for user in users %}
<li>{{ user.username|e }}</li>
{% endfor %}
</ul>
{% endif %}
Примечание
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 conditions, and
and or
can be used:
{% if temperature > 18 and temperature < 27 %}
<p>It's a nice day for a walk in the park.</p>
{% endif %}
For multiple branches elseif
and else
can be used like in PHP. You can
use more complex expressions
there too:
{% if product.stock > 10 %}
Available
{% elseif product.stock > 0 %}
Only {{ product.stock }} left!
{% else %}
Sold-out!
{% endif %}
Примечание
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 |
NAN (Not A Number) |
true |
INF (Infinity) |
true |
whitespace-only string |
true |
string «0» or „0“ |
false |
empty array |
false |
null |
false |
non-empty array |
true |
object |
true |