unset_arr.php

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> unset_arr.php </title>
<meta charset="UTF-8">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
</head>

<body>
<form method="post" action="">
<input type="text" name="usrname"><br>
<input type="submit">
</form>
<br>usrname:<br>

<?php
$arr = array(5 => 1, 12 => 2);
$arr[] = 56; // 等同于 $arr[13] = 56;
var_dump($arr);
$arr["x"] = 42; //添加1 个新元素x
var_dump($arr);
echo '<hr>';
unset($arr[5]); // 从数组中删除该元素5
echo 'arr unset $arr[5]';
echo '<hr>';
var_dump($arr);
unset($arr); // 删除整个数组
if(isset($arr))
var_dump($arr);
else
echo 'arr unset';
?>

usrname:

array  5 => int 1  12 => int 2  13 => int 56

array  5 => int 1  12 => int 2  13 => int 56  'x' => int 42

arr unset $arr[5]

array  12 => int 2  13 => int 56  'x' => int 42

arr unset

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