On Wednesday, March 30, 2011 7:29:42 PM UTC+2, Mike Meyer wrote:
>
> On Wed, 30 Mar 2011 10:21:41 -0700 (PDT)
> Jeff Rose <ros...@gmail.com> wrote:
>
> > Hola,
> > I'm looking for a function that updates a map value by calling a
> > function on it.
> >
> > (def foo {:a 1})
> >
> > So instead of this:
> > (assoc foo :a (inc (:a foo))) ; => {:a 2}
> >
> > Something like this:
> > (map-fn foo :a inc) ; => {:a 2}
> >
> > Does that exist somewhere, or should I be doing this in a different
> > way? If not, shouldn't it be included?
>
> Possibly you want update-in:
>
> (update-in foo [:a] inc) ; -> {:a 2}
>
> I'm not sure why there's not an "update" that replaces the list of
> keys with a single key.
>
> <mike
> --
> Mike Meyer <m...@mired.org> http://www.mired.org/consulting.html
> Independent Software developer/SCM consultant, email for more information.
>
> O< ascii ribbon campaign - stop html mail - www.asciiribbon.org
>
What if I want to update all values in a map? Is there something faster/more
idiomatic than this?
(reduce conj {} (map (fn [[k v]] [k (update-value-fn v)]) my-map))
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