How to clear the specified session in php

In PHP, you can use the unset() function and the predefined variable "$_SESSION" to clear the specified session, the syntax is "unset($_SESSION['session name']);".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

In php, clearing the specified session means deleting it $_SESSION The specified element of the array;

Simply put, clearing the specified session is the same as the operation of the array. Simply log out of an element of the $_SESSION array.

For example, when deleting $_SESSION['name'], you can use the unset() function directly, such as unset($_SESSION['name']); .

The unset() function can release the specified variable. Its syntax format is as follows:

unset(mixed $var [, mixed $...])

where $var is the variable to be released. The unset() function can receive multiple parameters. Between the parameters Use,separate.

Note: When using the unset() function to delete a single Session element, be careful not to omit the specific element name, that is, do not unregister the entire $_SESSION array at once, as this may cause accidental Unexpected errors.

[Example] Use the unset() function to delete the specified Session element.

<?php
    session_start();
    echo &#39;<pre class="brush:php;toolbar:false">&#39;;
    $str = &#39;PHP中文网&#39;;
    $arr = [&#39;删除 Session&#39;,&#39;$_SESSION&#39;];
    $_SESSION[&#39;name&#39;]  = $str;
    $_SESSION[&#39;url&#39;]   = &#39;https://www.php.cn/&#39;;
    $_SESSION[&#39;title&#39;] = $arr;
    echo &#39;定义一个 Session，如下所示：<br>&#39;;
    print_r($_SESSION);
    echo &#39;删除 Session 中名为 title 的元素：<br>&#39;;
    unset($_SESSION[&#39;title&#39;]);
    print_r($_SESSION);
?>

The running results are as follows:

定义一个 Session，如下所示：
Array
(
    [name] => PHP中文网
    [url] => https://www.php.cn/
    [title] => Array
        (
            [0] => 删除 Session
            [1] => $_SESSION
        )
)
删除 Session 中名为 title 的元素：
Array
(
    [name] => PHP中文网
    [url] => https://www.php.cn/
)

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