Two ways to delete key values ​​in associative arrays in PHP

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The main content of this article is to introduce to you two methods of deleting key values ​​​​in associative arrays in PHP.

Let’s look at the code directly:

The first method:

Use the unset() function: The unset() function can be used to unset keys and their values ​​in an associative array.

Syntax: void unset( $array_name['key_to_be_removed'] )

##The code example is as follows:

<?php
// 声明关联数组
$arr = array(
    "1" => "加",
    "2" => "减",
    "3" => "乘",
    "4" => "除"
);

// 关联数组中删除键1及其值
unset($arr[&#39;1&#39;]);

// 显示数组元素
var_dump($arr);

The running result is:

array (size=3)
  2 => string '减' (length=3)
  3 => string '乘' (length=3)
  4 => string '除' (length=3)

Note: unset can delete either a variable or a unit in the array, but it should be noted that the array will not be re-indexed.

Second method:

Use

array_diff_key() function: This function uses Gets the difference between one or more arrays. This function compares keys between one or more arrays and returns the difference between them.

Syntax:

array array_diff_key( $array_name, array_flip((array) ['keys_to_be_removed']

The code example is as follows:

<?php
// 声明关联数组
$arr = array(
    "1" => "春",
    "2" => "夏",
    "3" => "秋",
    "4" => "冬",
);

// 从关联数组中删除键1及其值
$result = array_diff_key($arr,
    array_flip((array) [&#39;1&#39;]));

// 显示数组元素
var_dump($result);

The running result is:

array (size=3)
  2 => string '夏' (length=3)
  3 => string '秋' (length=3)
  4 => string '冬' (length=3)

Note: The return value of the array_diff_key() function is to return a difference array, which includes all the arrays being compared (array1). But the key name is not in any other parameter array (array2 or array3, etc.).

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