python - python中下划线是什么意思

Question

这个问题已经有答案了:

Why does python use two underscores for certain things? [duplicate] (7 个回答)

已关闭 9 年前。

大家好，从我的问题中可以明显看出，我就像一个 Python 新手。当我阅读有关 python 的文档甚至 Stackoverflow 论坛时，我感到非常困惑......

他们为什么这样写

from __future__ import division

Future 一词周围的下划线是什么意思？我们是否应该在 python 解释器中像下划线一样使用它？这只是众多例子之一。任何帮助将不胜感激。

Answer 1

根据PEP 236在提议此模块的地方，双下划线使其成为保留名称。

[5] This ensures that a future_statement run under a release prior to
    the first one in which a given feature is known (but >= 2.1) will
    raise a compile-time error rather than silently do a wrong thing.
    If transported to a release prior to 2.1, a runtime error will be
    raised because of the failure to import __future__ (no such module
    existed in the standard distribution before the 2.1 release, and
    the double underscores make it a reserved name).