<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "GREEN", "B" => "brown", "yellow", "red");
print_r(array_uintersect_uassoc($array1, $array2, "strcasecmp", "strcasecmp"));
?>
Результат выполнения данного примера:
Array
(
[a] => green
[b] => brown
)