python中的装饰器
关于装饰器先看这一篇文章：
http://www.cnblogs.com/tingfenglin/p/5592385.html
写得比较全面的是这一篇：
http://blog.csdn.net/dreamcoding/article/details/8611578
1 def lazyproperty(func): #func: area 2 name = '_lazy_' + func.__name__ 3 @property 4 def lazy(self): 5 if hasattr(self, name): 6 return getattr(self, name) 7 else: 8 value = func(self) 9 setattr(self, name, value) 10 return value 11 return lazy 12 13 import math 14 15 class Circle: 16 def __init__(self, radius): 17 self.radius = radius 18 19 @lazyproperty 20 def area(self): 21 print('Computing area') 22 return math.pi * self.radius ** 2 23 24 @lazyproperty 25 def perimeter(self): 26 print('Computing perimeter') 27 return 2 * math.pi * self.radius 28 29 c=Circle(4.0) 30 c.area
程序中如果没有@property，第30行就要变成c.area()
