[swift-evolution] Removing enumerated?
patrickpijnappel at gmail.com
Sun Feb 5 18:47:26 CST 2017
Note that zip(a.indices, a) requires advancing the index twice each
iteration, which for non-array collections is not necessarily super
trivial. Considering we're talking about such a low-level operation as
iterating through a collection this might be worth considering.
Personally I'm in favor of adding indexed().
On Mon, Feb 6, 2017 at 3:14 AM, Ben Cohen via swift-evolution <
swift-evolution at swift.org> wrote:
> On Feb 5, 2017, at 08:12, Ben Cohen <ben_cohen at apple.com> wrote:
> >> On Feb 4, 2017, at 14:43, Dave Abrahams via swift-evolution <
> swift-evolution at swift.org> wrote:
> >> on Fri Feb 03 2017, Ben Cohen <swift-evolution at swift.org> wrote:
> >>>> On Feb 3, 2017, at 3:27 PM, Dave Abrahams via swift-evolution
> >>>> <swift-evolution at swift.org> wrote:
> >>>> I don't always make zip a method, but when I do, its argument label is
> >>>> “to:”
> >>> Hmm, that doesn’t sound very natural to me.
> >>> Then again the problem with “zip(with:)" is it’s already kind of a
> >>> term of art for a version that takes a function to combine the two
> >>> values.
> >>> There’s also the question of how to spell a non-truncating versions
> >>> (returning optionals or taking a pad value).
> >> Is there a use-case for such a zip?
> > Whenever it's not OK to not silently discard the elements in the longer
> list (which can be a correctness trap of zip if you're not careful). Say
> you're matching up contestants from two groups, but want to give byes to
> the unmatched contestants in the larger group. Or you're generating a list
> of positioned racers in a 8-car race, putting in a computer player when you
> run out of real players.
> Gah, accidental double-negation, meant "not OK to silently discard"
> >> --
> >> -Dave
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