rps.py

import random

print("Let's play some Rock, Paper, Scissors!")

options = ['rock', 'paper', 'scissors']
trumps = {'rock': ['scissors'], 'paper': ['rock'], 'scissors': ['paper']}
wins = 0
losses = 0

running = True
while running:
    option = input("What do you choose?: ")
    
    if option not in options:
        print('You must choose between ' + ', '.join(options))
        continue
    
    cpuOption = options[random.randrange(len(options))]
    
    print("You chose " + option + " while the computer chose " + cpuOption)
    
    if option == cpuOption:
        print("It's a tie! No one wins! Try again...")
        print("\n") # move down a line for readability
        continue
    
    won = False
    
    if cpuOption in trumps[option]:
        won = True
    
    if won:
        print("You win! Congratulations! Let's try again...")
        wins += 1
    else:
        print("You lose! Better luck next time! Let's try again...")
        losses += 1
        
    print("You've won %d time(s) and lost %d time(s)." % (wins, losses))
    print("\n") # move down a line for readability