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

class Property:
    def __init__(self, get_attrib_func):
        self.get_attrib_func = get_attrib_func
        self.set_attrib_func = None

    def __set__(self, instance, value):
        if not self.set_attrib_func:
            raise AttributeError("can't set attribute")
        self.set_attrib_func(instance, value)

    def __get__(self, instance, owner):
        return self.get_attrib_func(instance)

    def setter(self, set_attrib_func):
        self.set_attrib_func = set_attrib_func
        return self

2.简单的测试代码

class Person:
    def __init__(self, name, age):
        self._name = name
        self._age = age

    @Property  # name = Property(name)
    def name(self):
        return self._name

    @name.setter  # name = Property(name).setter(name)
    def name(self, name):
        self._name = name

    @Property  # age = Property(age)
    def age(self):
        return self._age

    # @age.setter  # age = Property(age).setter(age)
    # def age(self, age):
    #     self._age = age

    def __str__(self):
        return "<Person:{}:{}>".format(self._name, self._age)

    __repr__ = __str__

if __name__  == "__main__":
    p = Person("tom", 19)
    print(type(p.name), type(p.age))
    p.name = "jerry"  # OK
    print("~" * 100)
    p.age = 200  # AttributeError: can't set attribute