CODEWITHSUNDEEP
clojure
goldfrapp04
goldfrapp04

Reputation: 2355

Clojure map a set to another set directly?

user=> (map inc #{1 2 3})
(2 4 3)
user=> (into #{} (map inc #{1 2 3}))
#{4 3 2}

Is there a way to apply a function to a set and return a set directly?

Upvotes: 1

Views: 136

Answers (3)

muhuk
muhuk

Reputation: 16095

A slightly more generic way to do this is to use empty:

(defn my-map [f c]
  (into (empty c)
        (map f c)))

This yields following results:

(my-map inc #{1 2 3})  ;; => #{2 3 4}
(my-map inc [1 2 3])   ;; => [2 3 4] 
(my-map inc '(1 2 3))  ;; => (4 3 2)

It would work for other persistent collections as well.

Upvotes: 1

bsvingen
bsvingen

Reputation: 2759

With Clojure 1.7.0 (still in beta) you can do this using a transducer:

(into #{} (map inc) #{1 2 3})

Upvotes: 1

Daniel Compton
Daniel Compton

Reputation: 14569

As Alex said, fmap from algo.generic provides this function, although if you look at the source it's doing exactly the same as your code. I'd recommend just putting your function in a util namespace in your code, it's probably not worth pulling in a whole library for one function.

Upvotes: 1

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