Two ways to delete key values in associative arrays in PHP-PHP Problem-php.cn

In the previous article "Two methods for quickly downloading files from URL with PHP", I introduced two methods for PHP to download files from URL. Friends in need can read and learn. ~

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 theunset()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:

 "加", "2" => "减", "3" => "乘", "4" => "除" ); // 关联数组中删除键1及其值 unset($arr['1']); // 显示数组元素 var_dump($arr);

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The running result is:

Two ways to delete key values in associative arrays in PHP

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

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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:

 "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) ['1'])); // 显示数组元素 var_dump($result);

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The running result is:

Two ways to delete key values in associative arrays in PHP

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

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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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