Solving Hanging with Friends (Pt. 2)

Continued from Part 1, I’m off to write something to solve my Hanging with Friends games for me.

Because the two pieces of the puzzle (word list and next letter) are independent I can begin with either. I started with the letter frequency analysis because it seemed like a more tractable problem.

Ok, so it seemed easier but where should I start? Since I’m not totally clear on what it should do yet, I’ll start with the tests (aka how it should behave).

Given a list of viable words,

  • it should count how many words a letter appears in
  • it should only count a letter once per word
  • it should count each letter of the word

Here’s the full RSpec for those tests:


    describe "letter frequencies" do
      before(:each) do
        @words = ["lilly", "silly"]
      end

      it "should not return nil" do
        Frequency.letter_frequencies(@words).should_not be_nil
      end

      it "should return a hash" do
        Frequency.letter_frequencies(@words).is_a?(Hash).should be_true
      end

      it "should count the number of words with that letter" do
        freqs = Frequency.letter_frequencies(@words)
        freqs[:s].should == 1
        freqs[:y].should == 2
      end

      it "should not return a frequency larger than the number of words in the list" do
        freqs = Frequency.letter_frequencies(@words)
        freqs.values.count {|c| c> @words.length}.should == 0
      end
    end
    
    describe "letters per word" do
      before(:each) do
        word = "lilly"
        @letters = Frequency.letters_per_word(word)
      end
      it "should not return nil" do
        @letters.should_not be_nil
      end
      it "should return an array" do
        @letters.is_a?(Array).should be_true
      end
      it "should convert the letter to symbols" do
        @letters.count { |e| e.class == Symbol}.should == @letters.length
      end
      it "should only include repeated letters once" do
        @letters.count { |e| e == :l}.should == 1
      end
    end

Hmm, that’s a little more straightforward than I thought. Let’s make those tests green.

My first pass:


  class Frequency
    def self.letter_frequencies(words)
      freq = {}
      words.each do |word|
        letters_per_word(word).each do |letter|
          freq[letter] ||= 0
          freq[letter] += 1
        end
      end
      freq
    end
    
    def self.letters_per_word(word)
      chars = []
      word.each_char do |char| 
        char = char.to_sym
        chars << char unless chars.include? char 
      end
      chars
    end
  end

Ok, so more code to the tests than to the actual implementation. That seems about right...

Next we'll deal with how to make the word list contain only the words we actually want.

The most recent version of the code is available at GitHub: https://github.com/jeffweiss/hanging_solver.

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