python中的class_static的@classmethod的巧妙用法

class Goods:
    __discount = 0.8
    def __init__(self,name,money):
        self.__name = name
        self.__money = money
    @property
    def price(self):
        return self.__money*Goods.__discount
    @classmethod
    def change(cls,new_discount):#注意这里不在是self了，而是cls进行替换
        cls.__discount = new_discount

apple = Goods('苹果',5)
print(apple.price)
Goods.change(0.5) #这里就不是使用apple.change()进行修改了
print(apple.price)

class A(object):  
    bar = 1  
    def foo(self):  
        print 'foo'  

    @staticmethod  
    def static_foo():  
        print 'static_foo'  
        print A.bar  

    @classmethod  
    def class_foo(cls):  
        print 'class_foo'  
        print cls.bar  
        cls().foo()  
###执行  
A.static_foo()  
A.class_foo() 

class A():
 
    def __init__(self,name):
        self.name = name
        self.config = {'batch_size':A.bs}
    @classmethod
    def set_bs(cls,bs):
        cls.bs = bs
    def print_config(self):
        print (self.config)
 
A.set_bs(4)
a = A('test')
a.print_config()