array_intersect_ukey function in php

array_intersect_ukey() function of PHP is used to create a new array by matching the keys of two or more arrays with the help of a user define function or callback function. It is an inbuilt function of PHP.

Syntax:

Here,

$arr1,$arr2 and $arrN are PHP arrays and callback_function is a user define function which campare the keys and return TRUE or FALSE.

Example 1:

<?php
function callback_function($x,$y)
{
if ($x===$y)
  {
  return 0;
  }
  return ($x>$y)?1:-1;
}
$arr1= array("fruit1"=>"Apple","fruit2"=>"Banana","fruit3"=>"Orange","fruit4"=>"Pear");
$arr2= array("fruit5"=>"Banana","fruit6"=>"Banana","fruit3"=>"Orange","fruit4"=>"Litchi");
$result=array_intersect_ukey($arr1,$arr2,"callback_function");
echo "<pre>";
print_r($result);
?>

Output: