swap keys and values in a map

Question

Is there a function to swap the key and value of a given map. So given a map, I want the keys to become values, and values the keys.

(swap {:a 2 b 4}) => {2 :         


        

Answer 1

There's a function reverse-map in clojure.contrib.datalog.util, it's implemented as:

(defn reverse-map
  "Reverse the keys/values of a map"
  [m]
  (into {} (map (fn [[k v]] [v k]) m)))