This is a key example of a case where code speaks. Can you write an implementation of how you would want single() to work in Python code?
On Mon, Oct 30, 2017 at 2:49 AM, Ivan Pozdeev via Python-ideas < python-ideas@python.org> wrote: > > > On 30.10.2017 9:29, python-ideas-requ...@python.org wrote: > >> If I have understood your use-case, you have a function that returns a >> list of results (or possibly an iterator, or a tuple, or some other >> sequence): >> >> print(search(haystack, needle)) >> # prints ['bronze needle', 'gold needle', 'silver needle'] >> >> There are times you expect there to be a single result, and if there are >> multiple results, that is considered an error. Am I correct so far? >> > Correct. > >> If so, then sequence unpacking is your friend: >> >> result, = search(haystack, needle) >> >> <...> >> >> I *think* this will solve your problem. >> >> If not, can you please explain what "single()" is supposed to do, why it >> belongs in itertools, and show an example of how it will work. >> > That works. Too arcane in my book though (and others' too according to > https://stackoverflow.com/a/473337/648265), and the error messages are > cryptic in this use case. > It also cannot be a part of an expression, unlike next(). > > The initial post on the above link summarizes the suggested implementation > pretty well. > > -- > Regards, > Ivan > > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ > -- --Guido van Rossum (python.org/~guido)
_______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
