Avatar of Drew-Goddyn

Drew-Goddyn's solution

to Anagram in the Ruby Track

Published at Dec 02 2019 · 2 comments
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
  private

  attr_reader :term, :sorted_term

  public

  def initialize(term)
    @term = term.downcase
    @sorted_term = @term.chars.sort
  end

  def match(words)
    words.select do |word|
      word = word.downcase
      next if word == term

      word.chars.sort == sorted_term
    end
  end
end

Community comments

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

Don't take this the wrong way, I am just trying to help.

You don't need this part of your code.

  private

  attr_reader :term, :sorted_term

  public

What you have added doesn't do or add anything. In ruby class variables declared with @ are private, and class variables are available to every method in that class.

I hope that helps.

Avatar of Drew-Goddyn
Drew-Goddyn
Solution Author
commented 49 days ago

Hi Nzajt,

Thanks a lot for the comment! I think you misundertood what I'm actually making private here. It isn't trying to make the instance variables private, rather it is making the getter method generated by the attr_reader behind the scenes private.

If you're interested in why, take a look at Sandi Metz book "Practical Object Oriented Design in Ruby", specifically the section "Depend on Behavior, Not Data".

What this does is let me encapsulate the instance variables without exposing them externally.

(edited 49 days ago)

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.

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