function arrayGetDuplicate($array){ $duplicate = array(); $already = array(); foreach ($array as $key=>$value){ foreach ($array as $key2=>$value2) { if($key == $key2){ continue; } if(in_array($key2, $already)){ continue; } if($array[$key] == $array[$key2]){ $already[] = $key; $duplicate[] = $array[$key] ; } } } return $duplicate; }