如何检查PHP会话是否为空? [英] How do check if a PHP session is empty?

问题描述

这是不好的做法吗?

if ($_SESSION['something'] == '')
{
    echo 'the session is empty';
}

是否可以检查其是否为空或未设置?我实际上是在这样做:

Is there a way to check if its empty or it is not set? I'm actualy doing this:

if (($_SESSION['something'] == '') || (!isset($_SESSION['something'])) {
    echo 'the session is either empty or doesn\'t exist';
}

!isset只是检查$_SESSION['']是否存在，并且不检查数组中是否有值

Does !isset just checks if a $_SESSION[''] exist and doesn't check if, is there are values in the array or not

推荐答案

我会使用 isset 和 empty :

I would use isset and empty:

session_start();
if(isset($_SESSION['blah']) && !empty($_SESSION['blah'])) {
   echo 'Set and not empty, and no undefined index error!';
}

array_key_exists 是使用isset检查密钥的不错选择:

array_key_exists is a nice alternative to using isset to check for keys:

session_start();
if(array_key_exists('blah',$_SESSION) && !empty($_SESSION['blah'])) {
    echo 'Set and not empty, and no undefined index error!';
}

在读取或写入会话数组之前，请确保要调用session_start.

Make sure you're calling session_start before reading from or writing to the session array.

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