array_intersect_key

Syntax:array array_intersect_key ( array $array1 , array $array2 [, array $ ... ] )
Description:Computes the intersection of arrays using keys for comparison

<?php
$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

print_r(array_intersect_key($array1, $array2));
?>
    

OUTPUT

Array ( [blue] => 1 [green] => 3 )