janet/examples/frequencies.dst

# Get the number of occurences of elements in a set

(defn frequencies
 "Get the number of occurences of each value in a sequence."
 [s]
 (let [freqs @{}
       _ (foreach s (fn [x] 
          (let [n (get freqs x)]
           (put freqs x (if n (+ 1 n) 1)))))]
  freqs))