Mark Dickinson <dicki...@gmail.com> added the comment:
Either raising, or treating a zero-weight-sum as undefined behaviour and documenting that the sum of the weights should be positive sounds fine to me. -1 on the suggestion to (deliberately, by documented design) choose at random in this case. Mathematically, this situation doesn't make sense: as Tim said, it's analogous to choosing from an empty population. Ex: you have `nred` red balls and `nblue` blue balls in a bag. If you want to simulate drawing a single ball from the bag, then random.choices(["red", "blue"], [nred, nblue]) does the job. But in the case where `nred = nblue = 0`, the bag is empty and it's not possible to draw anything; in that case I'd expect an error. I definitely wouldn't expect to get either a red ball or a blue ball (with equal probability). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue38881> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
