array_diff_key() function in php

array_diff_key() function of PHP is used to calculate the difference of two or more arrays by comparing the keys of given arrays. It is an inbuilt function of PHP.

Syntax:

Here

$arr1,$arr2 and $arrN are arrays.

Example 1:

<?php
$arr1=array("fruit1"=>"Mango","fruit2"=>"Orange","fruit3"=>"Pear","fruit4"=>"Banana","fruit5"=>"Apple");
$arr2=array("fruit1"=>"Mango","fruit6"=>"Banana");
$arr3=array("fruit2"=>"Orange","fruit3"=>"Pear");
$new_arr=array_diff_key($arr1,$arr2,$arr3);
echo "<pre>";
print_r($new_arr);
?>

Output:

Example 2:

<?php
$arr1=array("Mango","Orange","Pear","Banana","Apple");
$arr2=array("Mango","Banana");
$new_arr=array_diff_key($arr1,$arr2);
echo "<pre>";
print_r($new_arr);
?>

Output: