PHP Manual . ... PHP 4 ) array_intersect -- Computes the intersection of arrays . array array_intersect ( array array1, array array2 [, array ...]) . array_intersect() returns an array containing all the values of array1 that are present in all the arguments. ... Example 1. array_intersect() example . array1 = array ("a" => "green", "red", "blue"); $array2 = array ("b" => "green", "yellow", "red"); $result = array_intersect ($array1, $array2); . ... Array ( [a] => green [0] => red ) . ...