PHP检查False还是Null [英] PHP check if False or Null

问题描述

当从函数返回时，如何检查变量是否为false/null也让我感到困惑.

I also get confused how to check if a variable is false/null when returned from a function.

何时使用empty()和何时使用isset()检查条件?

When to use empty() and when to use isset() to check the condition ?

推荐答案

对于函数的返回，请不要使用isset或empty，因为它们仅对变量起作用，并且仅在此处测试可能不存在的变量变量而不会触发错误.

For returns from functions, you use neither isset nor empty, since those only work on variables and are simply there to test for possibly non-existing variables without triggering errors.

对于函数返回，检查变量是否存在是没有意义的，所以只需执行以下操作:

For function returns checking for the existence of variables is pointless, so just do:

if (!my_function()) {
    // function returned a falsey value
}

要详细了解此内容，请参见 PHP isset和empty .

To read about this in more detail, see The Definitive Guide To PHP's isset And empty.

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