Python | 单下划线和双下划线可访问性

环境: Python 3.10.4

1. 总结

先放总结

	单下划线	双下划线
类属性和方法	True	False
子类调用父类属性和方法	True	False
模块函数	True	True

在实际开发过程中，强烈不推荐调用_或__开头的内容，像__str__之类除外。

2. 类

2.1. 属性

class Hello:
    def __init__(self, one, two):
        self._one = one
        self.__two = two


h = Hello(1, 2)
print(h._one)
print(h.__two)

Output

1
Traceback (most recent call last):
  File "/Users/yimt/Code/PycharmProjects/hello-python/hello.py", line 9, in <module>
    print(h.__two)
AttributeError: 'Hello' object has no attribute '__two'

2.2. 方法

class Hello:
    def _one(self):
        print('one')

    def __two(self):
        print('two')


h = Hello()
h._one() 
h.__two()

Output

Traceback (most recent call last):
  File "/Users/yimt/Code/PycharmProjects/hello-python/learn.py", line 1, in <module>
    import hello
  File "/Users/yimt/Code/PycharmProjects/hello-python/hello.py", line 11, in <module>
    h.__two()
AttributeError: 'Hello' object has no attribute '__two'
one

3. 模块

程序正常执行

hello.py

def _one():
    print('one')


def __two():
    print('two')

main.py

import hello

hello._one()
hello.__two()

Output

one
two