On Mar 30, 11:29 pm, Jozef Wagner <[email protected]> wrote:
> 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 <[email protected]> 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 <[email protected]>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))
(into {} (for [[k v] m] [k (f v)]))
(clojure.contrib.generic.functor/fmap f m)
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