On Tue, 13 Oct 2015 11:26:09 -0400, Random832 <random...@fastmail.com> wrote: > "R. David Murray" <rdmur...@bitdance.com> writes: > > > On Tue, 13 Oct 2015 14:59:56 +0300, Stefan Mihaila > > <stefanmihail...@gmail.com> wrote: > >> Maybe it's just python2 habits, but I assume I'm not the only one > >> carelessly thinking that "iterating over an input a second time will > >> result in the same thing as the first time (or raise an error)". > > > > This is the way iterators have always worked. > > It does raise the question though of what working code it would actually > break to have "exhausted" iterators raise an error if you try to iterate > them again rather than silently yield no items.
They do raise an error: StopIteration. It's just that the iteration machinery uses that to stop iteration :). And the answer to the question is: lots of code. I've written some: code that iterates an iterator, breaks that loop on a condition, then resumes iterating, breaking that loop on a different condition, and so on, until the iterator is exhausted. If the iterator restarted at the top once it was exhausted, that code would break. --David _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
