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to Nucleotide Count in the Clojure Track

Published at Jul 13 2018 · 0 comments
Test suite

Given a single stranded DNA string, compute how many times each nucleotide occurs in the string.

The genetic language of every living thing on the planet is DNA. DNA is a large molecule that is built from an extremely long sequence of individual elements called nucleotides. 4 types exist in DNA and these differ only slightly and can be represented as the following symbols: 'A' for adenine, 'C' for cytosine, 'G' for guanine, and 'T' thymine.

Here is an analogy:

  • twigs are to birds nests as
  • nucleotides are to DNA as
  • legos are to lego houses as
  • words are to sentences as...


The Calculating DNA Nucleotides_problem at Rosalind http://rosalind.info/problems/dna/

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


(ns nucleotide-count-test
  (:require [clojure.test :refer [deftest is]]

(deftest empty-dna-strand-has-no-adenosine
  (is (= 0 (nucleotide-count/count \A, ""))))

(deftest empty-dna-strand-has-no-nucleotides
  (is (= {\A 0, \T 0, \C 0, \G 0}
         (nucleotide-count/nucleotide-counts ""))))

(deftest repetitive-cytidine-gets-counted
  (is (= 5 (nucleotide-count/count \C "CCCCC"))))

(deftest repetitive-sequence-has-only-guanosine
  (is (= {\A 0, \T 0, \C 0, \G 8}
         (nucleotide-count/nucleotide-counts "GGGGGGGG"))))

(deftest counts-only-thymidine
  (is (= 1 (nucleotide-count/count \T "GGGGGTAACCCGG"))))

(deftest validates-nucleotides
  (is (thrown? Throwable (nucleotide-count/count \X "GACT"))))

(deftest counts-all-nucleotides
    (is (= {\A 20, \T 21, \G 17, \C 12}
           (nucleotide-count/nucleotide-counts s)))))
(ns nucleotide-count
  (:refer-clojure :exclude [count]))

(def nucleotide-counts frequencies)

(defn count [c dna]
  {:pre [(#{\A \T \C \G} c)]}
  (get (nucleotide-counts dna) c 0))

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