Monty Hall playing code

monty_hall.rb

def play_monty_hall(strategy)
	doors = [:car,:goat,:sheep]

	guess = doors.sample

	if strategy == :switch
		# the revealed door is one that's not the winning and not the one we guessed
		revealed_door = doors.reject{|door| door == :car || door == guess}.sample
		
		# we change our guess to the door that was not revealed (and not our guess)
		guess = doors.reject{|door| door == guess || door == revealed_door }.first
	end

	if guess == :car
		:win
	else
		:lose
	end
end

wins = 0
1000.times do
	wins += 1 if play_monty_hall(:switch) == :win
end

puts "When we switched we: "
puts "  won #{wins} times"

wins = 0
1000.times do
	wins += 1 if play_monty_hall(:stick) == :win
end

puts "When we sticked we: "
puts "  won #{wins} times"

results

phusion@tinco:~ $ ruby monty_hall.rb 
When we switched we: 
  won 688 times
When we sticked we: 
  won 324 times
phusion@tinco:~ $ ruby monty_hall.rb 
When we switched we: 
  won 664 times
When we sticked we: 
  won 311 times
phusion@tinco:~ $ ruby monty_hall.rb 
When we switched we: 
  won 661 times
When we sticked we: 
  won 345 times