$b ) ? 1 : -1; } $a1 = array("a"=>"red","b"=>"green","c"=>"blue"); $a2 = array("a"=>"red","b"=>"green","d"=>"blue"); $a3 = array("e"=>"yellow","a"=>"red","d"=>"blue"); $result = array_diff_uassoc($a1,$a2,$a3,"myfunction"); print_r($result);