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arturjzapater's solution

to Scrabble Score in the Elixir Track

Published at Oct 09 2020 · 0 comments
Test suite

Given a word, compute the scrabble score for that word.

Letter Values

You'll need these:

Letter                           Value
A, E, I, O, U, L, N, R, S, T       1
D, G                               2
B, C, M, P                         3
F, H, V, W, Y                      4
K                                  5
J, X                               8
Q, Z                               10


"cabbage" should be scored as worth 14 points:

  • 3 points for C
  • 1 point for A, twice
  • 3 points for B, twice
  • 2 points for G
  • 1 point for E

And to total:

  • 3 + 2*1 + 2*3 + 2 + 1
  • = 3 + 2 + 6 + 3
  • = 5 + 9
  • = 14


  • You can play a double or a triple letter.
  • You can play a double or a triple word.

Running tests

Execute the tests with:

$ mix test

Pending tests

In the test suites, all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by commenting out the relevant @tag :pending with a # symbol.

For example:

# @tag :pending
test "shouting" do
  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"

Or, you can enable all the tests by commenting out the ExUnit.configure line in the test suite.

# ExUnit.configure exclude: :pending, trace: true

If you're stuck on something, it may help to look at some of the available resources out there where answers might be found.


Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup

Submitting Incomplete Solutions

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


defmodule ScrabbleTest do
  use ExUnit.Case

  # @tag :pending
  test "empty word scores zero" do
    assert Scrabble.score("") == 0

  @tag :pending
  test "whitespace scores zero" do
    assert Scrabble.score(" \t\n") == 0

  @tag :pending
  test "scores very short word" do
    assert Scrabble.score("a") == 1

  @tag :pending
  test "scores other very short word" do
    assert Scrabble.score("f") == 4

  @tag :pending
  test "simple word scores the number of letters" do
    assert Scrabble.score("street") == 6

  @tag :pending
  test "complicated word scores more" do
    assert Scrabble.score("quirky") == 22

  @tag :pending
  test "scores are case insensitive" do
    assert Scrabble.score("OXYPHENBUTAZONE") == 41

  @tag :pending
  test "convenient scoring" do
    assert Scrabble.score("alacrity") == 13


ExUnit.configure(exclude: :pending, trace: true)
defmodule Scrabble do

  @one_point 'AEIOULNRST'
  @two_points 'DG'
  @three_points 'BCMP'
  @four_ponts 'FHVMY'
  @five_ponts 'K'
  @eight_points 'JX'
  @ten_ponts 'QZ'

  @doc """
  Calculate the scrabble score for the word.
  @spec score(String.t()) :: non_neg_integer
  def score(word) do
    |> String.upcase()
    |> to_charlist()
    |> Enum.map(&get_value/1)
    |> Enum.sum()

  defp get_value(letter) when letter in @one_point, do: 1
  defp get_value(letter) when letter in @two_points, do: 2
  defp get_value(letter) when letter in @three_points, do: 3
  defp get_value(letter) when letter in @four_ponts, do: 4
  defp get_value(letter) when letter in @five_ponts, do: 5
  defp get_value(letter) when letter in @eight_points, do: 8
  defp get_value(letter) when letter in @ten_ponts, do: 10
  defp get_value(_letter), do: 0

What can you learn from this solution?

A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that you could read more about to improve your understanding?