$RoomRefArr=array(); foreach ($data['packageRooms'] as $val){ $key=$val['packageRoomCode']; $RoomRefArr['roomReferences'][$key]=$val['roomReferences']; $RoomRefArr['occupancy'][$key]=$val['occupancy']; }

RoomRefArr := make(map[string]map[string][]string)
    for _, val := range data["packageRooms"] {
        key := val["packageRoomCode"]
        RoomRefArr["roomReferences"][key] = val["roomReferences"]
        RoomRefArr["occupancy"][key] = val["occupancy"]
    }