Hi Steven, To put this into perspective, I did some greps on Sagemath, being the largest Python project I have installed on this machine (1955 .py files).
Occurrences: enumerate: 922 zip: 585 itertools.product: 67 itertools.combinations: 18 itertools.islice: 17 chain: 14 (with or without itertools. prefix) This seems to confirm my gut feeling that "chain" just isn't that common an operation; even among itertools functions, product, combinations and islice are more common. Based on this I would say there is little justification to even put "chain" in builtins, let alone to give it dedicated syntax. I also note that * for repetition is only supported for a few iterables (list, tuple), incidentally the same ones which support + for sequence chaining. Stephan 2017-06-27 12:38 GMT+02:00 Steven D'Aprano <st...@pearwood.info>: > On Tue, Jun 27, 2017 at 11:01:32AM +0200, Stephan Houben wrote: >> Hi all, >> >> Is "itertools.chain" actually that common? >> Sufficiently common to warrant its own syntax? > > I think it's much more common than (say) sequence repetition: > > a = [None]*5 > > which has had an operator for a long, long time. > >> In my experience, "enumerate" is far more common >> among the iterable operations. >> And that doesn't have special syntax either. > > True. But enumerate is a built-in, and nearly always used in a single > context: > > for i, x in enumerate(sequence): > ... > > A stranger to Python could almost be forgiven for thinking that > enumerate is part of the for-loop syntax. > > In contrast, chaining (while not as common as, say, numeric addition) > happens in variable contexts: in expressions, as arguments to function > calls, etc. > > It is absloutely true that this proposal brings nothing new to the > language that cannot already be done. It's syntactic sugar. So I guess > the value of it depends on whether or not you chain iterables enough > that you would rather use an operator rather than a function. > >> A minimal proposal would be to promote "chain" to builtins. > > Better than nothing, I suppose. > > > > -- > 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/
