PHP array_diff_key() Function
Last Updated : 17 Mar 2025
This is an inbuilt function of PHP. This function was introduced in PHP 5.1. The array_diff_key() function compares the keys of two or more arrays, and returns entries from array1 that are not present in array2 or array3, etc.
Syntax
| Parameter | Description | Is compulsory |
|---|---|---|
| array1 | The array to compare from | compulsory |
| array2 | An array to compare against | compulsory |
| array3 | More arrays to compare against | Optional |
Return Type
Returns an array containing the entries from array1 that are not present in any of the other arrays.
Example 1
Output:
Array ( [3]=> Boi )
Example 2
Output:
Array( [20] => Laxman [30] => Rahul [40] => Ganguly [50] => Yuvi )
Example 3
Output:
Array ( [b] => Bed )
Example 4
Output:
Array ( [a1]=> red [c3]=> blue [d4]=> black )
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