利用描述符自定制property

版权声明：17602128911 https://blog.csdn.net/bus_lupe/article/details/86362058

class Lazyproperty:
    def __init__(self, func):
        self.func = func

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

class Room:
    # area = Lazyproperty(arg)
    def __init__(self, name, width, length):
        self.name = name
        self.width = width
        self.length = length

    # @property => area = property(area)
    # @property

    # @Lazyproperty => area = Lazyproperty(area); 返回的是Lazyproperty类的一个实例对象
    # 装饰器会执行Lazyproperty类的__init__函数
    @Lazyproperty
    def area(self):
        return self.width * self.length

bedroom = Room('卧室', 5, 3)

# 类 > 数据描述符 > 实例对象 > 非数据描述符
# 会执行修饰符类Lazyproperty的__get__方法
print(bedroom.area)