Vedran Čačić <ved...@gmail.com> added the comment: Yes, and these functions are completely fine for your personal library, if you need such things. But they really have no place in math module, since (1) they aren't always correct, (2) it's incredibly difficult to characterize exactly when they are, and (3) even when they are correct, they just give people wrong impression about floats somehow being decimal numbers.
If you need to use floats, reconcile yourself with the idea that they don't represent all decimal numbers, not even the ones with just one decimal place, and any algorithm dealing with decimal digits will be just an approximation. If you want the best approximation the humanity can muster, backed with empirical data and theoretical considerations, use the round() builtin. If you want to just have something that works according to your preconceived notions in some cases, while failing mysteriously in others, use your quick-and-dirty implementations. If you want exact decimal results, use the decimal module, and specify the rounding mode as you wish. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue41598> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
