When I need something like this, I usually rop a line on the module namespace that goes like:
first = lambda x: next(iter(x)) On 30 October 2017 at 23:09, Steven D'Aprano <st...@pearwood.info> wrote: > On Tue, Oct 31, 2017 at 07:51:02AM +1100, Cameron Simpson wrote: > >> return the(nodes) >> >> It's this kind of thing that expresses my intent better than the: >> >> node, = nodes >> return node >> >> idiom. > > If the intent is to indicate that there is only one node, then > "the(nodes)" fails completely. "The" can refer to plurals as easily as > singular: > > "Wash the dirty clothes." > (Later) "Why did you only wash one sock?" > > > The simplest implementation of this "single()" function I can think of > would be: > > def single(iterable): > result, = iterable > return result > > > That raises ValueError if iterable has too few or too many items, which > I believe is the right exception to use. Conceptually, there's no > indexing involved, so IndexError would be the wrong exception to use. > We're expecting a compound value (an iterable) with exactly one item. If > there's not exactly one item, that's a ValueError. > > > > -- > Steve > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
