Mark Dickinson <dicki...@gmail.com> added the comment:
[Tim] > Because it's a bit obscure, and in real life y is always known to be > positive, so the nearly obvious (x + y - 1) // y works fine. Whereas I find (x + y - 1) // y less obvious at first sight than -(-x // y). :-) I don't care about negative y - that's not my reason for preferring -(-x // y). The preference comes from the fact that -(-x // y) still does the right thing for non-integral cases. [Vladimir] > Say we're making a controller for a game engine GUI and need to figure out how to paint sprites. [...] For this example, I'd probably just use `ceil(x / y)`. For "real world" things with x and y representing counts of something tangible (pixels, work items, row or column count of a matrix, lines of text, bytes of memory used, ...), you have to go quite a long way before `ceil(x / y)` gives you the wrong answer due to floating-point errors. E.g. if you know the quotient is no larger than 10**6, you're safe for all y <= 10**10. (Or vice versa: if you know the quotient is at most 10**10, then you're safe for y <= 10**6.) > not __ceildiv__ [...] It would be a little odd (but only a little) to have __floor__, __ceil__, and __floordiv__ overloads, but not __ceildiv__. It probably wouldn't be long before someone requested it. I'll quieten down now and wait to see what other people think. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue46639> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
