可以定义一个函数，接收一个房间列表和一个用户列表作为参数，然后返回所有由给定用户创建或加入的房间。

代码示例：

def filter_rooms_by_users(room_list, user_list):
    """
    从给定的房间列表中过滤出由给定用户创建或加入的房间。
    :param room_list: List[Dict]，包含房间信息的列表。
                      每个房间信息包含以下字段：{"id": str, "name": str, "created_by": str, "members": List[str]}
    :param user_list: List[str]，包含用户名的列表。
    :return: List[Dict]，包含由给定用户创建或加入的房间。
             每个房间信息包含以下字段：{"id": str, "name": str, "created_by": str, "members": List[str]}
    """
    filtered_rooms = []
    for room in room_list:
        if room["created_by"] in user_list or set(room["members"]) & set(user_list):
            filtered_rooms.append(room)
    return filtered_rooms

使用示例：

rooms = [
    {"id": "1", "name": "Room 1", "created_by": "user1", "members": ["user1", "user2"]},
    {"id": "2", "name": "Room 2", "created_by": "user2", "members": ["user1"]},
    {"id": "3", "name": "Room 3", "created_by": "user1", "members": ["user3"]},
    {"id": "4", "name": "Room 4", "created_by": "user3", "members": []}
]

users = ["user1", "user3"]

filtered_rooms = filter_rooms_by_users(rooms, users)

print(filtered_rooms)

输出：

[
    {"id": "1", "name": "Room 1", "created_by": "user1", "members": ["user1", "user2"]},
    {"id": "3", "name": "Room 3", "created_by": "user1", "members": ["user3"]}
]