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 之间有区别吗?如果我进行双重布尔检查，这种方式是正确的还是多余的?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

这完全是多余的.empty 或多或少是 !isset($foo) || 的简写!$foo 和 !empty 类似于 isset($foo) &&$foo.IE.empty 与 isset 做相反的事情，并额外检查一个值的 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.

或者换句话说，empty 与 !$foo 相同，但如果变量不存在则不会抛出警告.这就是这个函数的要点:做一个布尔比较而不用担心设置的变量.

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.

手册是这样写的:

empty() 与(boolean) var相反，除了没有设置变量时不会产生警告.

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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