自定制property

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

    def __get__(self, instance, owner):
        print('get')
        # print(instance)
        # print(owner)
        if instance is None:
            return self

        res = self.func(instance)
        setattr(instance, self.func.__name__, res)
        return res

class Room:
    def __init__(self, width, length):
        self.width = width
        self.length = length

    @Lazyproperty
    def area(self):
        return self.width * self.length

    @property
    def area1(self):
        return self.width * self.length

r = Room(1, 2)

# print(Room.area)

print(r.area1)

print(r.area)
print(r.__dict__)
print(r.area)