On Apr 21, 2020, at 01:36, Serhiy Storchaka <storch...@gmail.com> wrote: > > 20.04.20 23:33, Andrew Barnert via Python-ideas пише: >> Should this print 1 or 2 or raise StopIteration or be a don’t-care? >> Should it matter if you zip(y, x, strict=True) instead? > > It should print 2 in both cases. The only way to determine whether the > iterator ends is to try to get its next value. And this value (1) will lost, > because there is no way to return it or "unput" to the iterator. There is no > reason to consume more values, so StopIteration is irrelevant. > > There is more interesting example: > > x = iter(range(5)) > y = [0] > z = iter(range(5)) > try: > zipped = list(zip(x, y, z, strict=True)) > except ValueError: # assuming that’s the exception you want? > assert zipped == [(0, 0, 0)] > assert next(x) == 2 > print(next(z)) > > Should this print 1 or 2? > > The simple implementation using zip_longest() would print 2, but more optimal > implementation can print 1.
You’re right; that’s the question I should have asked; thanks. As I said, I think either answer is probably acceptable as long as it’s documented (and, therefore, it’s also clear that the consequences have been thought through). _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/EAWRMFD3JOSMIGHRLOHYQZMWNKKVDBRU/ Code of Conduct: http://python.org/psf/codeofconduct/
