python描述符

class Type:
    def __init__(self, key, expect_type):
        self.key = key
        self.expect_type = expect_type

    def __get__(self, instance, owner):
        print('执行get方法')
        return instance.__dict__[self.key]

    def __set__(self, instance, value):
        print('执行set方法')
        if not isinstance(value, self.expect_type):
            raise TypeError('你传入的不是',self.expect_type)

        instance.__dict__[self.key]=value

    def __delete__(self, instance):
        print('执行delete方法')
        instance.__dict__.pop(self.key)


class People:
    name = Type('name', str)
    age = Type('age', int)

    def __init__(self, name, age):
        self.name = name
        self.age = age

p = People('alex', 11)
print(p.name)

 

class Type:
    def __init__(self, key, expect_type):
        self.key = key
        self.expect_type = expect_type

    def __get__(self, instance, owner):
        print('执行get方法')
        return instance.__dict__[self.key]

    def __set__(self, instance, value):
        print('执行set方法')
        if not isinstance(value, self.expect_type):
            raise TypeError('你传入的不是',self.expect_type)

        instance.__dict__[self.key]=value

    def __delete__(self, instance):
        print('执行delete方法')
        instance.__dict__.pop(self.key)


def deco(**kwargs):  # kwargs = {'name':str, 'age': int}
    def wrapper(obj):  # obj = People
        print('--->',kwargs)
        print('类名',obj)
        for key, val in kwargs.items():  # ('name',str),('age',int)

            setattr(obj, key, Type(key, val))
        return obj
    print(kwargs)
    return wrapper


@deco(name=str, age=int)  # @wrapper ==> People= wrapper(People) 
class People:
    def __init__(self, name, age):
        self.name = name
        self.age = age


p = People('alex', 11)

print(p.__dict__)