small refactoring

src/rosalind/basics.clj

@@ -1,24 +1,17 @@
(ns rosalind.basics)

(defn dna-counter-fn
  "This actually does the counting"
  [dna cnt]
  (let [l (first dna)
        r (rest dna)]
    (case l
        \A (def h (assoc cnt :A (+ 1 (:A cnt))))
        \G (def h (assoc cnt :G (+ 1 (:G cnt))))
        \C (def h (assoc cnt :C (+ 1 (:C cnt))))
        \T (def h (assoc cnt :T (+ 1 (:T cnt))))
        nil)
    (if (empty? r)
      h
      (recur r h))))

(defn dna-count
(defn count-dna
  "Counts DNA Neucleotides"
  [dna]
  (let [h (dna-counter-fn dna {:A 0 :C 0 :T 0 :G 0})]
  (let [h (reduce (fn [c base]
              (case base
                  \A (assoc c :A (+ 1 (:A c)))
                  \G (assoc c :G (+ 1 (:G c)))
                  \C (assoc c :C (+ 1 (:C c)))
                  \T (assoc c :T (+ 1 (:T c)))
                  nil))
            {:A 0 :C 0 :T 0 :G 0}
            dna)]
    [(:A h) (:C h) (:G h) (:T h)]))

(defn transcribe-dna

test/rosalind/basics_test.clj

@@ -6,7 +6,7 @@
  (testing "Counting DNA Nucleotides"
    (is (=
      [20 12 17 21]
      (dna-count "AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC"))))
      (count-dna "AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC"))))

  (testing "Transcribing DNA into RNA"
    (is (= "GAUGGAACUUGACUACGUAAAUU"