如何在Twig中检查null? [英] How to check for null in Twig?

问题描述

在Twig模板中，我应该使用哪种结构来检查值是否为NULL?

What construct should I use to check whether a value is NULL in a Twig template?

推荐答案

取决于您到底需要什么:

Depending on what exactly you need:

• is null 检查值是否为null :

{% if var is null %}
    {# do something #}
{% endif %}

is defined 检查变量是否已定义:

is defined checks whether the variable is defined:

{% if var is not defined %}
    {# do something #}
{% endif %}

此外， is sameas 测试对类型进行了严格的比较两个值，可能对于检查null以外的值(例如false)很有用:

Additionally the is sameas test, which does a type strict comparison of two values, might be of interest for checking values other than null (like false):

{% if var is sameas(false) %}
    {# do something %}
{% endif %}

这篇关于如何在Twig中检查null?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！