How do I mask out letters that don't match what's expected?

Question

My goal is to create a game of hangman. I wrote code similar to this:

c = []
players_guess = gets
b = "example"
b.scan(/./) {|letter| c << letter}

c.each do |letter|
  if letter == players_guess
    puts letter
  else
    puts "*"
  end
end  

The code checks if the player guessed the right letter from the password hidden in variable c, and then displays the password hidden behind the *s and only revealed guessed letters. But when I run the program, the result is always the same, it displays players_guess, and then gives seven *. What is wrong here?

Answer 1

Here's a simple way to do what you want:

word = "example"
puts "Type a letter: "
guess = gets.chomp
puts word.tr("^#{guess}", "*")

This uses the String#tr method to replace all but the guess to *.

The output if you typed e would be e*****e.

Answer 2

Your If/Then Logic is Wrong

Your code is as follows:

c.each do |letter|
  if letter == players_guess
    puts letter
  else
    puts "*"
  end
end

The conditional will generally be false, since no single letter is likely to match the entire line retrieved by gets. As a result, you get an asterisk printed for each letter in c.

Some Options to Fix Your Code

You can do a couple of things here.

1. Just show the string if the strings are equal.

   puts players_guess if b == players_guess.chomp
   

2. Use a counter in your loop to index into your arrays or strings.

   • http://www.ruby-doc.org/core-1.9.3/String.html#method-i-index
   • http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-5B-5D

3. Split both strings into an array, and compare the arrays, printing letters that match or an asterisk on a non-match.

   c.each_with_index do |char, idx|
     puts char == players_guess.scan(/./)[idx] ? char : '*'
   end