python之描述符的应用

class Foo:
    def __init__(self,key,hope_type):
        self.key=key
        self.hope_type=hope_type
    def __get__(self, instance, owner):
        print('输出get')
        return instance.__dict__[self.key]
    def __delete__(self, instance):
        print('输出delete')
        instance.__dict__.pop(self.key)
    def __set__(self, instance, value):
        if not isinstance(value,self.hope_type):
            raise TypeError('您输入的类型是%s'%self.hope_type)
        instance.__dict__[self.key]=value


class Test:
    name=Foo('name',str)
    age=Foo('age',int)
    def __init__(self,name,age,salary):
        self.name=name
        self.age=age
        self.salary=salary
f=Test('alex','18',200)