TWIG的 tests 学习

做逻辑判断的。目前支持的有

divisibleby null even odd sameas constant defined empty

divisibleby
检查是否能被整除

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

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

even
变量是否是偶数{{ var is even }}
{{ var is even }}

odd
变量是否是奇数

{{ var is odd }} 
{{ var is odd }}
 
 
sameas

检查变量的地址是否相同
{% 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

检查变量的值是否相同
{% 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

测试变量是否定义
{# 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

测试变量是否为空，empty的意思是：该变量已经定义，但他的值是 null false 或者是空字符串

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

{% if foo is empty %} 

    ... 

{% endif %} 


摘自 jiaochangyun的专栏