python math模块中的log2 [英] log2 in python math module

问题描述

为什么不存在?

import math
[x for x in dir(math) if 'log' in x]
>>> ['log', 'log10', 'log1p']

我知道我可以做log(x，2)，但是log2确实很常见，所以我有点困惑.

I know I can do log(x,2), but log2 is really common, so I'm kind of baffled.

哦，看来它仅在C99中定义，而不是在C90中定义，我想这回答了我的问题.还是有点傻.

Oh, it looks like it's only defined in C99, not C90, I guess that answers my question. Still seems kind of silly.

推荐答案

我认为您已经回答了自己的问题. :-)没有log2(x)，因为您可以执行log(x, 2).正如Python的禅宗( PEP 20 )所说，应该有一个-而且最好只有一种-很明显的方式."

I think you've answered your own question. :-) There's no log2(x) because you can do log(x, 2). As The Zen of Python (PEP 20) says, "There should be one-- and preferably only one --obvious way to do it."

也就是说，在问题3366 (向下滚动到最后3条消息)中考虑了log2在math模块中为Python 2.7和3.2添加了其他C99数学函数.

That said, log2 was considered in Issue3366 (scroll down to the last 3 messages) which added several other C99 math functions to the math module for Python 2.7 and 3.2.

编辑:在 Issue11888 中重新考虑了log2，并在Python 3.3中进行了添加.

Edit: log2 was reconsidered in Issue11888 and added in Python 3.3.

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