frequencies

added
1.2

ns
clojure.core

type
function

(frequencies coll)

Returns a map from distinct items in coll to the number of times
they appear.

                user=> (frequencies ['a 'b 'a 'a])
{a 3, b 1}
            
                ;; Turn a frequency map back into a coll.

(mapcat (fn [[x n]] (repeat n x)) {:a 2 :b 1 :c 3})
;;=> (:a :a :b :c :c :c)