Python-面向对象之property装饰器的实现（数据描述器）

Posted 2021-01-08 JerryZao

 

参考代码：

 1 from  functools import partial
 2 
 3 class Property:  # 数据描述符
 4     def __init__(self, fget=None, fset=None):
 5         self.fget = fget
 6         self.fset = fset
 7 
 8     def __get__(self, instance, owner):
 9         return partial(self.fget, instance)()
10 
11     def __set__(self, instance, value):
12         # instance._data = value # 修改了保护变量
13         self.fset(instance, value)
14 
15     def setter(self, fn):
16         self.fset = fn
17         return self
18 class A:
19     def __init__(self, data):
20         self._data = data  # 实例化的时候，保护属性直接注入
21 
22     @Property  # data = Property(data)
23     def data(self):
24         return self._data
25 
26     @data.setter  # data = data.setter(data)= Property(data)
27     def data(self, value):
28         self._data = value
29 
30 a = A(9)
31 print(a.__dict__)  # {\'_data\': 9}
32 
33 print(a.data)  # 是一个数字
34 
35 a.data = 8
36 print(a.__dict__)
37 print(a.data)  # 是一个数字
38 
39 a.data = 0
40 print(a.__dict__)
41 print(a.data)  # 是一个数字