python - 为什么 `float.is_integer` 中有下划线，但 `str.isnumeric` 中没有？

Question

看起来 float.is_integer是 Python 内置类型中唯一名称中带有下划线的“is”方法。 Examples that don't包括下划线:str.isalnum、str.isalpha、str.isdecimal、str.isdigit、str.isidentifier、str.islower、str.isnumeric、str.isprintable、str.isspace code>, str.istitle, str.isupper.

关于原因的任何线索？

通过 PEP 8 , 我希望所有这些名称都包含下划线。但实用胜于纯粹 ( PEP 20 )，因此在常用名称和短名称中省略下划线是有道理的。然而，这两种命名约定似乎都是向后兼容的结果(以 logging 模块作为典型示例)。

Answer 1

A similar question已在 Python 错误跟踪器上被问到:

Compare isinstance, issubclass, and islower to is_integer, is_fifo, and is_enabled. In Python 3.6, of all the names in the standard library starting with is, I count 69 names with the underscore and 91 without. It seems better to pick one way or the other and stick with it. I would recommend using the underscore, for legibility.

答案(来自 Python 核心开发人员 R. David Murray)是:

Yep, that would be nice. But Python has evolved over time, and we must maintain backward compatibility. The names are what they are.

鉴于问题中的数字，is_integer 似乎不是唯一带有下划线的方法。