Python编程之基础知识练习_003

练习内容：
模拟property描述器。

1.实现一个类，模拟property数据描述器

 1 class Property:
 2     def __init__(self, get_attrib_func):
 3         self.get_attrib_func = get_attrib_func
 4         self.set_attrib_func = None
 5 
 6     def __set__(self, instance, value):
 7         if not self.set_attrib_func:
 8             raise AttributeError("can't set attribute")
 9         self.set_attrib_func(instance, value)
10 
11     def __get__(self, instance, owner):
12         return self.get_attrib_func(instance)
13 
14     def setter(self, set_attrib_func):
15         self.set_attrib_func = set_attrib_func
16         return self

2.简单的测试代码

 1 class Person:
 2     def __init__(self, name, age):
 3         self._name = name
 4         self._age = age
 5 
 6     @Property  # name = Property(name)
 7     def name(self):
 8         return self._name
 9 
10     @name.setter  # name = Property(name).setter(name)
11     def name(self, name):
12         self._name = name
13 
14     @Property  # age = Property(age)
15     def age(self):
16         return self._age
17 
18     # @age.setter  # age = Property(age).setter(age)
19     # def age(self, age):
20     #     self._age = age
21 
22     def __str__(self):
23         return "<Person:{}:{}>".format(self._name, self._age)
24 
25     __repr__ = __str__
26 
27 if __name__  == "__main__":
28     p = Person("tom", 19)
29     print(type(p.name), type(p.age))
30     p.name = "jerry"  # OK
31     print("~" * 100)
32     p.age = 200  # AttributeError: can't set attribute