为什么将模块导入为_< name>在另一个模块中? [英] Why are modules imported as _<name> in another module?

问题描述

在Python标准库中有几种情况，其中导入的模块名称中带有前导下划线(_).我想知道为什么这样做是有必要的，因为无论如何它都是以模块的名称命名的，并且from ... import *将尊重__all__变量的导入内容.

There are several cases in the Python standard library where modules are imported with a leading underscore (_) in their name. I wonder why this is necessary, as it is under the module's name anyways and from ... import * will respect the __all__ variable for what to import.

有人知道为什么要使用/必要吗?

Does anyone know why this is used/necessary?

一个示例是argparse，它具有以下导入:

An example is argparse which has the following imports:

import collections as _collections
import copy as _copy
import os as _os
import re as _re
import sys as _sys
import textwrap as _textwrap

推荐答案

在Python中，单个前划线表示这是实现细节，而不是API的一部分".

In Python a single leading underscore means "this is an implementation detail, not part of the API".

这里的要点是要清楚，导入模块(在您的示例中为argparse)使用导入的，但并未将其作为其自身的一部分公开. API-即，您(作为API的客户端)不应依赖argparse.collections可用-如果要collections，则必须显式导入.

The point here is to make clear that the importing module (argparse in your example) uses the imported one but does not expose them as part of it's own API - ie, you (as a client of the API) should not rely on argparse.collections being available - if you want collections, you have to import it explicitely.

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