A Monty Hall Simulation. Try to win a car!

montyhall.py

# Monty Hall Simulator
# Raymond Ho
# September 5th, 2014
# Run -> python montyhall.py

import random

def greet():
	# Using the 'statement continuation character '\'
	print "\nWelcome to the Monty Hall Simulator, created by Raymond Ho.\n" \
		+ "This program was inspired by the TV show, Numb3rs.\nYour goal is to " \
		+ "win a car, by picking the correct card.\nIf you lose, you go home " \
		+ "with a goat. No one wants a goat.\nYou will get an option to switch " \
		+ "your choice after a goat is reveiled.\nWill you switch or stick " \
		+ "with your original choice? Goodluck!\n"

# Generate a list of numbers given input
# Return the list, with the car position
def generateList(inputx):

	# Initialize a list of all zeros.
	List = [0] * inputx
	carIndex = random.randint(0, inputx-1)

	# Set that position to be the prize
	List[carIndex] = 1

	return List, carIndex

def revealGoat(List, userchoice):
	while True:
		goat = random.randint(0, len(List) - 1)
		if goat is not userchoice and List[goat] == 0:
			return goat

# Chooses a number given a range that's not any of the indexes.
def getOtherChoice(rangeSize, choiceIndex, goatIndex):
	for i in range(rangeSize):
		if i is not choiceIndex and i is not goatIndex:
			return i

# Presents user with information and gives interactive options.
def interactiveChoices(inputx = 3):

	List, carIndex =  generateList(inputx)

	print "Below are %s choices. Pick one." % (inputx)
	print "[x] " * inputx
	for i in range(inputx):
		print '(%s)' % i,

	while True:
		choice = int(raw_input('\nYour choice: '))
		if choice in range(inputx):
			break
		else: print 'Please enter one the numbers above.'

	goatIndex = revealGoat(List, choice)
	print 'Position (%s) contains a goat!' % goatIndex
	print 'Given this information, would you like to change your choice?'

	switch = raw_input('y/n: ' )
	if switch.lower().startswith('y'):
		choice = getOtherChoice(inputx, choice, goatIndex)
		print 'Your choice is now (%s)' % (choice)
	else:
		print 'The car is at position (%s)' % (carIndex)

	# Chose the car
	if choice == carIndex:
		print 'You won the brand new car!'
		return 0
	else:
		print 'You lost. Enjoy your goat!'
		return 1


# Used to show switching raises chances of winning.
def runSwitchSimulator(times, inputx = 3, switch = True):

	s = 'with' if switch else 'without'
	print 'Running %s times, %s switching.' % (times, s)

	win = lose = 0

	for _ in range(times):
		List, carIndex = generateList(inputx)
		# Generate random choice
		choice = random.randint(0, inputx - 1)

		goatIndex = revealGoat(List, choice)

		# To switch, or not to switch..
		if switch:
			choice = getOtherChoice(inputx, choice, goatIndex)

		# Test
		if choice == carIndex: win += 1
		else : lose += 1

	print 'Wins: %s | Losses: %s' % (win, lose)
	print 'Win Percentage: %i' % (win / float(times) * 100)
	print

# Times to run the interactive simulation.
def main(times = 1):

	greet()
	win = lose = 0
	for _ in range(times):
		if interactiveChoices() == 0:
			win += 1
		else: lose += 1

	print 'Wins: %s | Losses: %s' % (win, lose)
	print 'Win Percentage: %i' % (win / float(times) * 100)
	print

if __name__ == '__main__':

	# Interactive
	main()

	# Simulators, un/comment to run.
	runSwitchSimulator(100000, 3, True)
	runSwitchSimulator(100000, 3, False)

	print 'Your chances of winning are doubled if you switch. Why?'