If you want to get an array which contain all the entries of an array and have keys that are present in some other arrays for this you can use a predefined function array_intersect_key ( array $array1 , array $array2 [, array $... ] ).
array_intersect_key() returns an array containing all the entries of array1 which have keys that are present in all other arguments.

Here is a example which will explain this function-

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

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

The above example will output:

array(2) {
  ["blue"]=> int(1)
  ["green"]=> int(3)
}