通过属性在列表中查找对象

users = [
    {"id": 1, "name": "Alice", "age": 30},
    {"id": 2, "name": "Bob", "age": 25},
    {"id": 3, "name": "Charlie", "age": 35}
]

def find_user_by_id(user_list, user_id):
    for user in user_list:
        if user["id"] == user_id:
            return user
    return None

# 使用示例
found_user = find_user_by_id(users, 2)
print(found_user)  # 输出: {'id': 2, 'name': 'Bob', 'age': 25}

# 使用字典提高查找效率
user_dict = {user["id"]: user for user in users}

def find_user_by_id_fast(user_dict, user_id):
    return user_dict.get(user_id, None)

# 使用示例
found_user_fast = find_user_by_id_fast(user_dict, 2)
print(found_user_fast)  # 输出: {'id': 2, 'name': 'Bob', 'age': 25}

def safe_find_user_by_id(user_list, user_id):
    for user in user_list:
        if "id" in user and user["id"] == user_id:
            return user
    return None