DRYing up Rock Paper Scissors

Question

I\'m a novice ruby programmer and although this code works, I\'m wondering how I can improve it. I have very limited knowledge on lambdas and procs and the like, but any advice

Answer 1

I think a proc or other similar setup is probably overkill. Just use inline-ifs:

def rps(roll)
  raise "Choose rock, paper, or scissors" if roll.nil?
  roll_ops = ["rock", "paper", "scissors"]
  pick = roll_ops.sample
  result = if roll == pick
    "tie"
  else
    case roll
    when "scissors"
      pick == "paper" ? 'win' : 'lose'
    when "rock"
      pick == "scissors" ? 'win' : 'lose'
    when "paper" then
      pick == "rock" ? 'win' : 'lose'
    end
  end
  puts "#{pick}, #{result}"
end

rps("scissors")

I removed your extra else that was supposed to handle non-input. Better to use errors in such a case.

There are a couple tricks here:

1- The inline-ifs. Those should be pretty clear.

2- The result variable is set equal to the return value of the if expression. This is a handy trick that you can use because in Ruby, everything is an expression!

If you are interested in using a lambda for this, it should work pretty well too:

def rps(roll)
  raise "Choose rock, paper, or scissors" if roll.nil?
  roll_ops = ["rock", "paper", "scissors"]
  pick = roll_ops.sample
  did_win = lambda do |choice|
    return choice == pick ? 'win' : 'lose'
  end
  result = if roll == pick
    "tie"
  else
    case roll
    when "scissors"
      did_win.call('paper')
    when "rock"
      did_win.call('scissors')
    when "paper" then
      did_win.call('rock')
    end
  end
  puts "#{pick}, #{result}"
end