经典类属性和新式类属性

经典类只@property 没有setter 和deleter

class A(object):
    def __init__(self,price):
        self.__price=price
    @property    
    def price(self):
        return self.__price
    @price.setter
    def price(self,value):
        self.__price=value

@price.deleter
    def price(self):
        print '@price.deleter'

a=A(1.23)
print(a.price)
a.price=23.4
print(a.price)
del a.price

结果：

1.23

23.4

del attr