RNA v2 solution

rna_transcription_v2.ex

defmodule RNATranscription do
  @guanine ?G
  @adenine ?A
  @cystosine ?C
  @uracil ?U
  @thymine ?T

  @doc """
  Transcribes a character list representing DNA nucleotides to RNA

  ## Examples

  iex> RNATranscription.to_rna('ACTG')
  'UGAC'
  """
  @spec to_rna([char]) :: [char]
  def to_rna(dna) do
    Enum.map(dna, fn dna_char ->
      case dna_char do
        @guanine -> @cystosine
        @cystosine -> @guanine
        @thymine -> @adenine
        @adenine -> @uracil
      end
    end)
  end
end