修改类属性

例子一：

一下是修改类属性，

class counter:    count = 0      def __init__(self):        self.__class__.count+=1 #此时类属性被类和所有类实例共享print counter.count # 0c=counter()print c.count # 1d=counter() print d.count #2print counter.count #2

例子二：

class counter(object):    count=0    class_co=0    def __init__(self):        self.count+=1  #实例所拥有        counter.class_co+=1print counter.count,counter.class_co # 0 0c=counter()print c.count,c.class_co # 1 1a=counter()print a.count,c.class_co # 1 2