why doesn\'t it exist?
import math
[x for x in dir(math) if \'log\' in x]
>>> [\'log\', \'log10\', \'log1p\']
I know I can do log(x,2)
I'm not sure that there is that you want, but:
-- From math point of view you can do for example math.log(x)/math.log(2).
-- If input X has an integral type and you are waiting for the integral rounded result - you can do it rather faster with right shifting. This works with SHR command and without Taylor series + local interpolation, which is under the hood of libc log() calls.
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."
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.
Edit: log2 was reconsidered in Issue11888 and added in Python 3.3.