Avatar of paulfioravanti

paulfioravanti's solution

to Resistor Color in the Ruby Track

Published at Jul 27 2019 · 0 comments
Instructions
Test suite
Solution

Resistors have color coded bands, where each color maps to a number. The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.

These colors are encoded as follows:

  • Black: 0
  • Brown: 1
  • Red: 2
  • Orange: 3
  • Yellow: 4
  • Green: 5
  • Blue: 6
  • Violet: 7
  • Grey: 8
  • White: 9

Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array: Better Be Right Or Your Great Big Values Go Wrong.

More information on the color encoding of resistors can be found in the Electronic color code Wikipedia article


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 resistor_color_test.rb

To include color from the command line:

ruby -r minitest/pride resistor_color_test.rb

Source

Maud de Vries, Erik Schierboom https://github.com/exercism/problem-specifications/issues/1458

Submitting Incomplete Solutions

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

resistor_color_test.rb

require 'minitest/autorun'
require_relative 'resistor_color'

# Common test data version: 1.0.0 edf1778
class ResistorColorTest < Minitest::Test
  def test_black
    # skip
    assert_equal 0, ResistorColor.color_code("black")
  end

  def test_white
    skip
    assert_equal 9, ResistorColor.color_code("white")
  end

  def test_orange
    skip
    assert_equal 3, ResistorColor.color_code("orange")
  end

  def test_colors
    skip
    expected = ["black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white"]
    assert_equal expected, ResistorColor::COLORS
  end
end
# frozen_string_literal: true

module ResistorColor
  COLORS = %w[
    black
    brown
    red
    orange
    yellow
    green
    blue
    violet
    grey
    white
  ].freeze

  module_function

  def color_code(color)
    COLORS.index(color)
  end
end

Community comments

Find this solution interesting? Ask the author a question to learn more.

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?