[swift-evolution] [Pitch] Add `mapValues` method to Dictionary

[Dan Appel]

>A value-value map is just simpler and cleaner, while almost always giving
you what you need.
+1

On Mon, May 23, 2016 at 10:59 PM Brent Royal-Gordon via swift-evolution <
swift-evolution at swift.org> wrote:

> > I have a small remark though, wouldn’t it be better to let transform be
> of type (Key, Value) throws -> T instead of (Value) throws -> T? You can
> just ignore the key (with _) if you don’t need it, but I think it might
> come in handy in some cases.
>
> The problem is, that closes the door to writing many simple maps in
> functional style. For instance, this:
>
>         dictionaryOfNumbers.mapValues(abs)
>
> Would have to become this:
>
>         dictionaryOfNumbers.mapValues { _, v in abs(v) }
>
> (It *might* be possible to do it with `$1`, but I'm not sure; there are
> some limitations around that.)
>
> A value-value map is just simpler and cleaner, while almost always giving
> you what you need.
>
> --
> Brent Royal-Gordon
> Architechies
>
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>
-- 
Dan Appel
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