Clojurepalooza homework - Sentiment scoring for words

sentiment-scoring.clj

(def test-responses [{:r 5, :c "This is awesome!"}
                {:r 1, :c "This sucks!"}
                {:r 3, :c "This is all right."}])


(defn clean-contents
  [response]
  (update-in response
             [:c]
             (comp (partial re-seq #"[a-z]+")
                   clojure.string/lower-case)))


(defn response->word-map
  "Takes a response in format {:r Integer :c [vector of words]} and returns a map
  associating each word in the response with the response's rating."
  [words response]
  (->> (interleave (:c response)
                   (repeat [(:r response)]))
       (apply hash-map)
       (merge-with concat words)))


(defn average-word-score
  "Takes a kv pair of [word [scores]] and returns a pair of
   the word and a map of ratings to probabilities that a response
   containing the word has the given rating."
  [word [scores]]
  [word (->> (frequencies scores)
             (map (fn [[k v]]
                    [k (/ v (count scores))]))
             (into {}))])


(defn score-sentiments
  "Takes a col of responses in format {:r Integer :c String} and returns a map
  associating each word found in the response contents with its average rating."
  [responses]
  (->> responses
       (map clean-contents)
       (reduce response->word-map {})
       (map average-word-score)
       (into {}))

(score-sentiments test-responses)

{"all" {3 1},
   "right" {3 1},
   "sucks" {1 1},
   "awesome" {5 1},
   "is" {3 1/2, 5 1/2}
   "this" {3 1/3, 1 1/3, 5 1/3}}