On 9/12/19 7:37 am, Guido van Rossum wrote:
def first(it, /, default=None): it = iter(it) try: return next(it) except StopIteration: return default
Can you provide any insight into why you think it's better for it never to raise an exception, as opposed to raising something other than StopIteration when the iterator is empty and no default is specified? There seem to be two kinds of use case for this: 1. The iterator may or may not be empty, and you don't want the hassle of having to catch an exception. 2. You expect the iterator to never be empty; if it is, then it's a bug, and you would like to get an exception, but not StopIteration because that can mess other things up. Your version of the function seems to be aimed exclusively at case 1. If it were to raise ValueError on an empty iterable unless a default were explicitly given, it would address both cases. -- Greg _______________________________________________ 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/SW4F6BQDXBIHGRVE42REWJY53LMR6TEH/ Code of Conduct: http://python.org/psf/codeofconduct/
