只有在函数里(不一定是构造函数),以__开头的变量才是私有变量,看代码:
class A:
def init(self):
self.data1=1
self.data2=2
self.__data3=3
self.__data4=44
def fun1(self):
print(self.__data4)
self.data5=5
object_a=A()
object_a.__data4=4
print(object_a.__data4)
object_a.fun1()
print(dir(object_a))
输出:
4
44
[’_A__data3’, ‘_A__data4’, ‘class’, ‘__data4’, ‘delattr’, ‘dict’, ‘dir’, ‘doc’, ‘eq’, ‘format’, ‘ge’, ‘getattribute’, ‘gt’, ‘hash’, ‘init’, ‘init_subclass’, ‘le’, ‘lt’, ‘module’, ‘ne’, ‘new’, ‘reduce’, ‘reduce_ex’, ‘repr’, ‘setattr’, ‘sizeof’, ‘str’, ‘subclasshook’, ‘weakref’, ‘data1’, ‘data2’, ‘data5’, ‘fun1’]
我用实例object_a也定义了一个__data4变量,但是__data4和类里面的__data4并不是同一个变量,调用dir()函数可知,形如_A__data4的才是私有变量