Clojure highest 3 values of a map

Question

Hi l'm trying to do a function that returns the 3 most commom strings

  (take 3 (sort-by val > (frequencies s))))

(freq ["hi" "hi" "hi" "ola" "hello" "hello" "string" "str" "ola" "hello" "hello" "str"])

l've got this so far but a noticed that if there are more than 1 string with the same frenquency it won't return. Is there a way to filter the values of the frequencies funcition by their highest (eventually the top 3 highest)?

Thanks in advance.

Answer 1

I would propose slightly different solution which involves inverting frequencies map with group-by value (which is the items' count):

(->> data
     frequencies
     (group-by val))

;;{3 [["hi" 3]],
;; 2 [["ola" 2] ["str" 2]],
;; 4 [["hello" 4]],
;; 1 [["string" 1]]}

so the only thing you need is to just sort and process it:

(->> data
     frequencies
     (group-by val)
     (sort-by key >)
     (take 3)
     (mapv (fn [[k vs]] {:count k :items (mapv first vs)})))

;;[{:count 4, :items ["hello"]}
;; {:count 3, :items ["hi"]}
;; {:count 2, :items ["ola" "str"]}]