为什么要同时检查isset()和！empty() [英] Why check both isset() and !empty()

问题描述

isset和!empty之间是否存在差异.如果我进行双重布尔检查，这种方法是正确的还是多余的?而且有没有更短的方法来做同样的事情?

Is there a difference between isset and !empty. If I do this double boolean check, is it correct this way or redundant? and is there a shorter way to do the same thing?

isset($vars[1]) AND !empty($vars[1])

推荐答案

这是完全多余的. empty或多或少是!isset($foo) || !$foo的简写，并且!empty与isset($foo) && $foo类似. IE. empty执行与isset相反的操作，并另外检查值的真实性.

This is completely redundant. empty is more or less shorthand for !isset($foo) || !$foo, and !empty is analogous to isset($foo) && $foo. I.e. empty does the reverse thing of isset plus an additional check for the truthiness of a value.

换句话说，empty与!$foo相同，但是如果变量不存在，则不会发出警告.这就是该功能的重点:进行布尔比较，而不必担心会设置变量.

Or in other words, empty is the same as !$foo, but doesn't throw warnings if the variable doesn't exist. That's the main point of this function: do a boolean comparison without worrying about the variable being set.

手册内容如下:

empty()与(boolean) var，相反，不同之处在于未设置变量时不生成警告.

您可以在这里简单地使用!empty($vars[1]).

You can simply use !empty($vars[1]) here.

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