PHP-正确检查$ _POST ['variable']是否发布 [英] PHP - proper check if $_POST['variable'] is posted

问题描述

我要检查是否发布了$ _POST ['submit'].

I want to check if $_POST['submit'] is posted.

我的原始代码是:

if ($_POST['submit']) { }

但是我有一个PHP通知，其中包含以下代码-未定义的索引:在...中提交"

But I have a PHP notice with this code - "Undefined index: submit in..."

所以要删除通知，我必须这样写:

So to remove the notice I have to write this:

if (isset($_POST['submit'])) { }

但这是没有意义的，因为$ _POST数组是全局数组，并且它始终返回true. 另外，如果我想在没有PHP通知的情况下检查$ _POST ['submit']是否不为0，我必须这样写:

But this is pointless because $_POST array is global and it return always true. Also if I want to check if $_POST['submit'] is not 0 without PHP notice I have to write this:

if (isset($_POST['submit']) && $_POST['submit'] != 0) { }

在这种情况下，我更喜欢:

In this particular case I prefer:

if ($_POST['submit']) {}

但是在这里，我得到了PHP通知.

But here I get the PHP notice.

那哪种方法最合适/可以接受?

So which way is the most proper/accepted?

谢谢

推荐答案

isset($_POST['submit'])检查是否在$_POST数组中设置了submit键.它不仅检查$_POST数组是否存在，因此不是毫无意义的".如果要检查是否包含0的 not falsey (== false)值，而不会触发错误，则empty就是这样的:

isset($_POST['submit']) checks if the submit key is set in the $_POST array. It doesn't just check whether the $_POST array exists and is therefore not "pointless". If you want to check whether the value is not falsey (== false), which includes 0, without triggering an error, that's what empty is for:

if (!empty($_POST['submit']))

与

if ($_POST['submit'])

但该值不存在时不触发通知.

but without triggering a notice should the value not exist.

有关详尽的说明，请参见有关PHP的isset和空的权威指南.

See The Definitive Guide To PHP's isset And empty for an exhaustive explanation.

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