calc-counts.clj

(defn match-count
" Given key, k, returns number of occurrences of k in collection, coll.
"
  [k coll]
  (let [match?  (fn [i x]
                  (if (= k x)   ;; closure on k
                    (inc i)
                    i))]
    (reduce match? 0 coll)))

(defn calc-counts
" Returns a list of counts for the occurrences of each key of keys, ks,
  within the collection, coll.
"  
  [ks coll]
  (pmap #(match-count % coll) ks))