> -----Original Message----- > From: Python-ideas [mailto:python-ideas-bounces+tritium- > list=sdamon....@python.org] On Behalf Of Steven D'Aprano > Sent: Thursday, May 18, 2017 9:01 AM > To: python-ideas@python.org > Subject: Re: [Python-ideas] fnmatch.filter_false > > On Thu, May 18, 2017 at 12:07:05AM -0400, tritium-l...@sdamon.com wrote: > > > > At the cost of a slight inefficiency, you could use the pure Python > > > equivalent given in the docs: > > > > > > https://docs.python.org/3/library/fnmatch.html#fnmatch.filter > > > > > > > > > fnmatch.filter(names, pattern) > > > > > > Return the subset of the list of names that match pattern. It is > > > the same as [n for n in names if fnmatch(n, pattern)], but implemented > > > more efficiently. > > > > > > So your filter_false is: > > > > > > [n for n in names if not fnmatch(n, pattern)] > > > > > > which avoids the need for the copy-and-paste anti-pattern. > > > > I ran a test on the same dataset using listcomps. The modified version of > > filter is still 22.<some noise>, the unmodified version is still 19.<some > > noise>. However the listcomp method is 41.<some noise>. That > performance > > is important, at least to me. > > 41 what? Nanoseconds? Hours? For how many files? *wink*
41 "integer units of whatever timeit reports with". I would have to look, but iirc it's seconds for 10000 runs. I am not on unix. > In any case, are you running on Linux or Unix? If so, try replacing the > fnmatch with fnmatchcase, since that avoids calling os.path.normcase (a > no-op on Linux) twice for each file. > > If you want to reduce the number of function calls even more, try this > untested code: > > # using an implementation detail is a bit naughty > match = fnmatch._compile_pattern(pattern).match > results = [n for n in names if match(n) is None] > > > > > -- > 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/
