On Mon, Nov 26, 2018, 17:38 Steven D'Aprano <st...@pearwood.info wrote: > On Mon, Nov 26, 2018 at 02:06:52PM -0800, Michael Selik wrote: > > If you know the input is sizeable, why not check its length instead of > the > > map's? > > The consumer of map may not be the producer of map. > > You might know that alist supports len(), but by the time I see it, I > only see map(f, alist), not alist itself. >
Then you have no way of knowing whether it is safe to use "len" or not. >
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