<?php $a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow"); $a2=array("a"=>"red","f"=>"green","g"=>"blue"); $a3=array("h"=>"red","b"=>"green","g"=>"blue"); $result=array_diff_assoc($a1,$a2,$a3); print_r($result); ?>