继续上次的进度:https://www.cnblogs.com/flashBoxer/p/9847521.html
正文: 装饰类在类中有两种不通的方式使用装饰器，第一个和我们之前做过的函数非常相似:在类的方法上应用。这也是当时引入装饰器的原因之一
一些常用的装饰器已经内置到python中，像@classmethod @staticmethod @property。这三个装饰器我们之前都介绍过，这段就不翻译了(打字手酸，偷懒下)
下面的Circle 类使用了@classmethod @staticmethod和@property三个装饰器
class Circle: def __init__(self, radius): self._radius = radius @property def radius(self): """Get value of radius""" return self._radius @radius.setter def radius(self, value): """Set radius, raise error if negative""" if value >= 0: self._radius = value else: raise ValueError("Radius must be positive") @property def area(self): """Calculate area inside circle""" return self.pi() * self.radius**2 def cylinder_volume(self, height): """Calculate volume of cylinder with circle as base""" return self.area * height @classmethod def unit_circle(cls): """Factory method creating a circle with radius 1""" return cls(1) @staticmethod def pi(): """Value of π, could use math.pi instead though""" return 3.1415926535