Nucleotide Count

Challenge Overview

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

Visit the nucleotide-count exercise on Exercism to read the full instructions and download the exercise files.

Community Solutions

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The following are the top 3 community solutions by stars:

Solution 1 by @chicolismo (⭐ 0) — View on Exercism
Solution 2 by @hl4 (⭐ 0) — View on Exercism
Solution 3 by @Rohankapri (⭐ 0) — View on Exercism

Source: Exercism sml/nucleotide-count

💡 View Solution

type result = {a: int, c: int, g: int, t: int}

fun nucleotideCounts (strand: string) : result =
  foldl
    (fn (x, {a, c, g, t}) =>
       case x of
         #"A" => {a = a + 1, c = c, g = g, t = t}
       | #"C" => {a = a, c = c + 1, g = g, t = t}
       | #"G" => {a = a, c = c, g = g + 1, t = t}
       | #"T" => {a = a, c = c, g = g, t = t + 1}