TWIG的 tests 学习

文章来源：http://twig.sensiolabs.org/doc/tests/index.html

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 %}

null

{{ var is null }}

even

变量是否是偶数

{{ var is even }}

odd

变量是否是奇数

{{ 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 %}




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 %}




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 %}




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 %}