Python实现简易Linq

 1 class LinQUtil(object):
 2     """
 3     模拟C#的linq功能
 4     """
 5 
 6     def __init__(self, collection, func):
 7         """
 8         初始化
 9         :param collection:需要处理的list
10         :param func: 处理的函数
11         """
12         self.collection = collection
13         self.func = func
14 
15     def where(self):
16         """
17         根据where添加查询
18         :return:
19         """
20         try:
21             return list(filter(self.func, self.collection))
22         except Exception as e:
23             print(e)
24             return list()
25 
26     def first_or_default(self):
27         try:
28             res = list(filter(self.func, self.collection))
29             if res:
30                 return res[0]
31             else:
32                 return dict()
33         except Exception as e:
34             print(e)
35             return dict()
36 def main():
37     # 从数据库查询出形如[{},{}..]的数据
38     data_list = get_user_list_dal()
39     # 使用Linq匹配到符合条件的数据
40     data_list_where = LinQUtil(data_list, func=lambda x: x.get(‘city_id‘) == 73).first_or_default()
41 
42     print(data_list_where)
43     print(len(data_list_where))
44 
45 
46 if __name__ == ‘__main__‘:
47     main()