Mark Dickinson <dicki...@gmail.com> added the comment:
> Shouldn't the two approaches provide the same answer? In a word, no. :-) math.floor(1/0.01) involves *two* operations, and there's an intermediate rounding step which happens to round the true mathematical result of 1/0.01 up to 100.0. Taking the floor of that then (of course) gives 100.0. 1//0.01 is the single-operation equivalent, that doesn't include an intermediate round. There are lots of other cases where a combination of two or more operations is mathematically equivalent to a single operation, but produces a different result due to an intermediate round; for example, things like `log(n) / log(2)` versus `log2(n)`, or `round(x, 2)` versus `round(100.0*x)/100.0`. There's unfortunately no way to square the circle here that doesn't cause surprises in at least some corner cases. I'm almost sure this issue is a duplicate, but I haven't found a good target for that duplicate yet. I'll continue searching. ---------- nosy: +mark.dickinson _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue39703> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
