TWIG's tests learning_PHP tutorial

Making logical judgments. Currently supported are

divisibleby null even odd sameas constant defined empty

divisibleby
Check if it is divisible

{% if loop.index is divisibleby(3) %}
...
{% endif %}
{% if loop.index is divisibleby(3) %}
...
{% endif %}

null
{{ var is null }}
{{ var is null }}

even
Whether the variable is even {{ var is even }}
{{ var is even }}

odd
Whether the variable is an odd number

{{ var is odd }} 

{{ var is odd }}

 
 
sameas

Check if the addresses of variables are the same
{% if foo.attribute is sameas(false) %} 

The foo attribute really is the ``false`` PHP value 

{% endif %} 

{% if foo.attribute is sameas(false) %}

The foo attribute really is the ``false`` PHP value

{% endif %}
 
constant

Check if the values ​​of variables are the same
{% if post.status is constant('Post::PUBLISHED') %} 

The status attribute is exactly the same as Post::PUBLISHED 

{% endif %} 

{% if post.status is constant('Post::PUBLISHED') %}

The status attribute is exactly the same as Post::PUBLISHED

{% endif %}
 
defined

Test whether the variable is defined 
{# defined works with variable names #} 

{% if foo is defined %} 

... 

{% endif %} 



{# and attributes on variables names #} 

{% if foo.bar is defined %} 

... 

{% endif %} 



{% if foo['bar'] is defined %} 

... 

{% endif %} 

{# defined works with variable names #}

{% if foo is defined %}

...

{% endif %}
{# and attributes on variables names #}

{% if foo.bar is defined %}

...

{% endif %}
{% if foo['bar'] is defined %}

...

{% endif %}
 
empty

Test whether the variable is empty. Empty means: the variable has been defined, but its value is null false or an empty string 

{# evaluates to true if the foo variable is null, false, or the empty string #} 

{% if foo is empty %} 

... 

{% endif %} 



Excerpted from jiaochangyun’s column



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