lujanfernaud's solution to Anagram on the Ruby track

Instructions

Test suite

Solution

Note:

This exercise has changed since this solution was written.

Given a word and a list of possible anagrams, select the correct sublist.

Given "listen" and a list of candidates like "enlists" "google" "inlets" "banana" the program should return a list containing "inlets".

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 anagram_test.rb

To include color from the command line:

ruby -r minitest/pride anagram_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.

anagram_test.rb

require 'minitest/autorun'
require_relative 'anagram'

# Common test data version: 1.4.0 baaf092
class AnagramTest < Minitest::Test
  def test_no_matches
    # skip
    detector = Anagram.new('diaper')
    anagrams = detector.match(["hello", "world", "zombies", "pants"])
    expected = []
    assert_equal expected, anagrams
  end

  def test_detects_two_anagrams
    skip
    detector = Anagram.new('master')
    anagrams = detector.match(["stream", "pigeon", "maters"])
    expected = ["maters", "stream"]
    assert_equal expected, anagrams.sort
  end

  def test_does_not_detect_anagram_subsets
    skip
    detector = Anagram.new('good')
    anagrams = detector.match(["dog", "goody"])
    expected = []
    assert_equal expected, anagrams
  end

  def test_detects_anagram
    skip
    detector = Anagram.new('listen')
    anagrams = detector.match(["enlists", "google", "inlets", "banana"])
    expected = ["inlets"]
    assert_equal expected, anagrams
  end

  def test_detects_three_anagrams
    skip
    detector = Anagram.new('allergy')
    anagrams = detector.match(["gallery", "ballerina", "regally", "clergy", "largely", "leading"])
    expected = ["gallery", "largely", "regally"]
    assert_equal expected, anagrams.sort
  end

  def test_does_not_detect_non_anagrams_with_identical_checksum
    skip
    detector = Anagram.new('mass')
    anagrams = detector.match(["last"])
    expected = []
    assert_equal expected, anagrams
  end

  def test_detects_anagrams_case_insensitively
    skip
    detector = Anagram.new('Orchestra')
    anagrams = detector.match(["cashregister", "Carthorse", "radishes"])
    expected = ["Carthorse"]
    assert_equal expected, anagrams
  end

  def test_detects_anagrams_using_case_insensitive_subject
    skip
    detector = Anagram.new('Orchestra')
    anagrams = detector.match(["cashregister", "carthorse", "radishes"])
    expected = ["carthorse"]
    assert_equal expected, anagrams
  end

  def test_detects_anagrams_using_case_insensitive_possible_matches
    skip
    detector = Anagram.new('orchestra')
    anagrams = detector.match(["cashregister", "Carthorse", "radishes"])
    expected = ["Carthorse"]
    assert_equal expected, anagrams
  end

  def test_does_not_detect_a_anagram_if_the_original_word_is_repeated
    skip
    detector = Anagram.new('go')
    anagrams = detector.match(["go Go GO"])
    expected = []
    assert_equal expected, anagrams
  end

  def test_anagrams_must_use_all_letters_exactly_once
    skip
    detector = Anagram.new('tapper')
    anagrams = detector.match(["patter"])
    expected = []
    assert_equal expected, anagrams
  end

  def test_words_are_not_anagrams_of_themselves_case_insensitive
    skip
    detector = Anagram.new('BANANA')
    anagrams = detector.match(["BANANA", "Banana", "banana"])
    expected = []
    assert_equal expected, anagrams
  end
end

class Anagram
  def initialize(word)
    @word = word
  end

  def match(candidates)
    candidates.select { |candidate| anagram?(candidate) }
  end

  private

  def anagram?(candidate)
    !candidate.casecmp(word).zero? && chars_for(candidate) == chars_for(word)
  end

  def chars_for(word)
    word.downcase.chars.sort
  end

  attr_reader :word
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?

lujanfernaud's solution

to Anagram in the Ruby Track