python3访问限制，对私有变量的访问，修改

 公有变量直接访问

>>> class Student(object):
...     def __init__(self,name,score):
...             self.name = name
...             self.score = score
...     def print_score(self):
...             print('%s:%s' %(self.name, self.score))
...
>>> ll = Student('lilu',99)
>>> ll
<__main__.Student object at 0x0000000000A3C550>
>>> ll.name
'lilu'
>>> ll.score
99

 私有变量无法直接访问,可以用特殊方法调用（变量前加上双下划线）

>>> class Student(object):
...     def __init__(self,name,score):
...             self.__name = name
...             self.__score = score
...     def print_score(self):
...             print('%s:%s' %(self.__name,self.__score))
...
>>> lm = Student('lime',66)
>>> lm
<__main__.Student object at 0x0000000000A3C7F0>
>>> lm.score
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Student' object has no attribute 'score'
>>> lm.name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Student' object has no attribute 'name'
>>> '''不能直接访问__name是因为Python解释器对外把__name变量改成了_Student__name，所以，仍然可以通过_Student__name来访问__name变量'''
>>> lm._Student__name
'lime'
>>> lm._Student__score
66

 可以通过内置函数，调用内置函数来修改变量值

>>> class Student(object):
...     def __init__(self,name,score):
...             self.__name = name
...             self.__score = score
...     def print_score(self):
...             print('%s:%s' %(self.__name,self.__score))
...     def get_score(self):
...             return self.__score
...     def get_name(self):
...             return self.__name
...     def set_score(self,score):
...             self.__score = score
...     def set_name(self,name):
...             self.__name = name
>>> zyt = Student('zhaoyouting',98)
>>> zyt.get_name()
'zhaoyouting'
>>> zyt.get_score()
98
>>> lgx =Student('linggengxin',88)
>>> lgx.set_score(99)
>>> lgx.get_score()
99
>>> lgx.set_name('LINGGENGXIN')
>>> lgx.get_name()
'LINGGENGXIN'