phpの配列の追加について

以下の場合にはarray_merge()を使います

array1=(1,2,3)
array2=(4,5,6)
$array = array_merge($array1,$array2);

以下の場合には以下のように対応することで配列を追加することができます

// array("3LDK" => array(000000,00001,...,00005), "2LDK" => array(20000,20001,...,3005)) などのように部屋の間取りに対応する配列を作成する
if($room_layout == "4K以上"){
        $leased_rooms["4K以上"][] = $room_id;
      }elseif($room_layout == "3LDK"){
        $leased_rooms["3LDK"][] = $room_id;
      }elseif($room_layout == "3DK"){
        $leased_rooms["3DK"][] = $room_id;
      }elseif($room_layout == "3K"){
        $leased_rooms["3K"][] = $room_id;
      }elseif($room_layout == "2LDK"){
        $leased_rooms["2LDK"][] = $room_id;
      }elseif($room_layout == "2DK"){
        $leased_rooms["2DK"][] = $room_id;
      }elseif($room_layout == "2K"){
        $leased_rooms["2K"][] = $room_id;
      }elseif($room_layout == "1LDK"){
        $leased_rooms["1LDK"][] = $room_id;
      }elseif($room_layout == "1DL"){
        $leased_rooms["1DK"][] = $room_id;
      }elseif($room_layout == "1K"){
        $leased_rooms["1K"][] = $room_id;
      }elseif($room_layout == "1R"){
        $leased_rooms["1R"][] = $room_id;
      }else{
        $leased_rooms["間取り希望なし"][] = $room_id;
      }