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DanielEFrampton's solution

to Scrabble Score in the Ruby Track

Published at Mar 12 2020 · 0 comments
Instructions
Test suite
Solution

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

Examples

"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

Extensions

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

For installation and learning resources, refer to the Ruby resources page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

Run the tests from the exercise directory using the following command:

ruby scrabble_score_test.rb

To include color from the command line:

ruby -r minitest/pride scrabble_score_test.rb

Source

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.

scrabble_score_test.rb

require 'minitest/autorun'
require_relative 'scrabble_score'

class ScrabbleTest < Minitest::Test
  def test_empty_word_scores_zero
    assert_equal 0, Scrabble.new('').score
  end

  def test_whitespace_scores_zero
    skip
    assert_equal 0, Scrabble.new(" \t\n").score
  end

  def test_nil_scores_zero
    skip
    assert_equal 0, Scrabble.new(nil).score
  end

  def test_scores_very_short_word
    skip
    assert_equal 1, Scrabble.new('a').score
  end

  def test_scores_other_very_short_word
    skip
    assert_equal 4, Scrabble.new('f').score
  end

  def test_simple_word_scores_the_number_of_letters
    skip
    assert_equal 6, Scrabble.new('street').score
  end

  def test_complicated_word_scores_more
    skip
    assert_equal 22, Scrabble.new('quirky').score
  end

  def test_scores_are_case_insensitive
    skip
    assert_equal 41, Scrabble.new('OXYPHENBUTAZONE').score
  end

  def test_convenient_scoring
    skip
    assert_equal 13, Scrabble.score('alacrity')
  end
end
=begin
Write your code for the 'Scrabble Score' exercise in this file. Make the tests in
`scrabble_score_test.rb` pass.

To get started with TDD, see the `README.md` file in your
`ruby/scrabble-score` directory.
=end

class Scrabble
  def initialize(input)
    @input = input || ''
  end

  def self.score(input)
    new(input).score
  end

  def score
    @input.split('').reduce(0) do |total_score, character|
      total_score += score_value(character.downcase)
    end
  end

  def score_value(character)
    return 1 if /[aeioulnrst]/.match?(character)
    return 2 if /[dg]/.match?(character)
    return 3 if /[bcmp]/.match?(character)
    return 4 if /[fhvwy]/.match?(character)
    return 5 if /[k]/.match?(character)
    return 8 if /[jx]/.match?(character)
    return 10 if /[qz]/.match?(character)
    0
  end
end

Community comments

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DanielEFrampton's Reflection

I chose to use regex matching to solve this rather than putting together a score-table hash, but there might be a way to use that to get the overall length down. I also suspect that there's a way to condense my `score_value` method.