Python中要想定义的方法或者变量只能在类内部使用不被外部使用，可以在方法和变量前面加两个下划线，让其变为私有方法或私有变量。类外部可以通过 ”_类名__私有属性（方法）名“ 访问私有属性（方法）。

class Person:__work = 'teacher'def __init__(self,name,age):self.name = nameself.__age = agedef run(self):print(self.__age,self.__work)def __eat(self):print('1111')

__work是私有类变量，类外是无法访问的

if __name__ == '__main__':
print(Person.__work)
Traceback (most recent call last):File "C:/Users/wangli/PycharmProjects/Test/test/test.py", line 20, in <module>print(Person.__work)
AttributeError: type object 'Person' has no attribute '__work'

__work是私有类变量，类外类实例对象是无法访问的

if __name__ == '__main__':test1 = Person('王大力','22')
print(test1.__work)
Traceback (most recent call last):File "C:/Users/wangli/PycharmProjects/Test/test/test.py", line 21, in <module>print(test1.__work)
AttributeError: 'Person' object has no attribute '__work'

__age是私有实例变量，类外类实例对象是无法访问的

if __name__ == '__main__':test1 = Person('王大力','22')
print(test1.__age)
Traceback (most recent call last):File "C:/Users/wangli/PycharmProjects/Test/test/test.py", line 21, in <module>print(test1.__age)
AttributeError: 'Person' object has no attribute '__age'

__work是私有类变量，__age是私有实例变量，类内是可以访问的

if __name__ == '__main__':test1 = Person('王大力','22')
test1.run()
22 teacher
Process finished with exit code 0

__eat（）是私有方法，类外是无法访问的

if __name__ == '__main__':test1 = Person('王大力','22')
print(test1.__eat())
Traceback (most recent call last):File "C:/Users/wangli/PycharmProjects/Test/test/test.py", line 21, in <module>print(test1.__eat())
AttributeError: 'Person' object has no attribute '__eat'

__work是私有类变量，__age是私有实例变量，__eat（）是私有方法，类外部可以通过 ”_Person___私有属性（方法）名“ 访问私有属性（方法）

if __name__ == '__main__':print(Person._Person__work)test1 = Person('王大力','22')print(test1._Person__work)print(test1._Person__age)
test1._Person__eat()
teacher
teacher
22
1111
Process finished with exit code 0