rock-paper-scissors redesign of https://codereview.stackexchange.com/questions/231695/first-attempt-python-rock-paper-scissors#231700

rps-nocomments.py

import random


class RockPaperScissors:
    """
    Class to handle an instance of a Rock-Paper-Scissors game
    with unlimited rounds.
    """

    def __init__(self):
        """
        Initialize the variables for the class
        """
        self.wins = 0
        self.losses = 0
        self.ties = 0
        self.options = {'rock': 0, 'paper': 1, 'scissors': 2}

    def random_choice(self):
        """
        Chooses a choice randomly from the keys in self.options.
        :returns: String containing the choice of the computer.
        """

        return random.choice(list(self.options.keys()))

    def check_win(self, player, opponent):
        """
        Check if the player wins or loses.
        :param player: Numeric representation of player choice from self.options
        :param opponent: Numeric representation of computer choice from self.options
        :return: Nothing, but will print whether win or lose.
        """

        result = (player - opponent) % 3
        if result == 0:
            self.ties += 1
            print("The game is a tie! You are a most worthy opponent!")
        elif result == 1:
            self.wins += 1
            print("You win! My honor demands a rematch!")
        elif result == 2:
            self.losses += 1
            print("Haha, I am victorious! Dare you challenge me again?")

    def print_score(self):
        """
        Prints a string reflecting the current player score.
        :return: Nothing, just prints current score.
        """
        print(f"You have {self.wins} wins, {self.losses} losses, and "
              f"{self.ties} ties.")

    def run_game(self):
        """
        Plays a round of Rock-Paper-Scissors with the computer.
        :return: Nothing
        """
        while True:
            userchoice = input("Choices are 'rock', 'paper', or 'scissors'.\n"
                               "Which do you choose? ").lower()
            if userchoice not in self.options.keys():
                print("Invalid input, try again!")
            else:
                break
        opponent_choice = self.random_choice()
        print(f"You've picked {userchoice}, and I picked {opponent_choice}.")
        self.check_win(self.options[userchoice], self.options[opponent_choice])


if __name__ == "__main__":
    game = RockPaperScissors()
    while True:
        game.run_game()
        game.print_score()

        while True:

            continue_prompt = input('\nDo you wish to play again? (y/n): ').lower()
            if continue_prompt == 'n':
                print("You are weak!")
                exit()
            elif continue_prompt == 'y':
                break
            else:
                print("Invalid input!\n")
                continue

rps.py

import random


class RockPaperScissors:
    """
    Class to handle an instance of a Rock-Paper-Scissors game 
    with unlimited rounds.
    """

    def __init__(self):
        """
        Initialize the variables for the class
        """
        
        # Wins are counted in self.wins
        self.wins = 0
        
        # Losses are counted in self.losses
        self.losses = 0
        
        # Ties are counted in self.ties
        self.ties = 0
        
        # The valid options for the RPS game are defined here as a dict.
        # This is the equivalent of an enum in some languages which converts 
        # text-representation of something into a numeric value, and is 
        # critical for win/loss checking in the check_win function.
        self.options = {'rock': 0, 'paper': 1, 'scissors': 2}

    def random_choice(self):
        """
        Chooses a choice randomly from the keys in self.options.
        :returns: String containing the choice of the computer.
        """
        
        return random.choice(list(self.options.keys()))

    def check_win(self, player, opponent):
        """
        Check if the player wins or loses.
        :param player: Numeric representation of player choice from self.options
        :param opponent: Numeric representation of computer choice from self.options
        :return: Nothing, but will print whether win or lose.
        """
        
        result = (player - opponent) % 3
        if result == 0:
            # Tie game, adjust self.ties count by one, and print 
            # the notice of a tie.
            self.ties += 1
            print("The game is a tie! You are a most worthy opponent!")
        elif result == 1:
            # Player won, adjust self.wins count by one and 
            # print a notice of a win.
            self.wins += 1
            print("You win! My honor demands a rematch!")
        elif result == 2:
            # Player lost, adjust self.losses count by one and 
            # print a notice of a loss.
            self.losses += 1
            print("Haha, I am victorious! Dare you challenge me again?")

    def print_score(self):
        """
        Prints a string reflecting the current player score.
        :return: Nothing, just prints current score.
        """
        
        # Uses f-strings to replace string contents rather than using 
        # straight string concatenation. Python >= 3.6 only.
        print(f"You have {self.wins} wins, {self.losses} losses, and "
              f"{self.ties} ties.")

    def run_game(self):
        """
        Plays a round of Rock-Paper-Scissors with the computer.
        :return: Nothing
        """
        
        # Get player choice, and don't stop until player provides a valid choice.
        # Utilizes self.options.keys() to get valid choices, which we have 
        # already defined when we created the game (see __init__ function)
        while True:
            # We can do 'input().lower()' directly to get lowercase input from 
            # the user, which saves us redefining the variable again.
            userchoice = input("Choices are 'rock', 'paper', or 'scissors'.\n"
                               "Which do you choose? ").lower()
            if userchoice not in self.options.keys():
                # If choice not in valid options, error and get input again.
                print("Invalid input, try again!")
            else:
                # Valid input provided, so break this loop and continue with game.
                break

        # Opponent's choice is randomly decided by the random_choice() function 
        # in the game's class.
        opponent_choice = self.random_choice()
        
        # Now, we state what player and computer chose. Uses f-strings
        # again, Python >= 3.6 only.
        print(f"You've picked {userchoice}, and I picked {opponent_choice}.")
        
        # Check who won, adjust score accordingly.
        self.check_win(self.options[userchoice], self.options[opponent_choice])


if __name__ == "__main__":
    # The game is now a class so we need an object to hold the 'instance' of the game
    game = RockPaperScissors()
    # Now, we just need to *run* the game, which we'll do in a loop here.
    while True:
        # This handles running the game and printing your score each round
        game.run_game()  # Runs the 'round' of the game.
        game.print_score()  # Prints the current score of the game.
        
        # Now, we have to determine if we're playing another round.
        while True:
            # Get answer from user if we're doing another round.
            continue_prompt = input('\nDo you wish to play again? (y/n): ').lower()
            if continue_prompt == 'n':
                # Quit the game.
                print("You are weak!")
                exit()  # Just exit the program here since we're done playing.
            elif continue_prompt == 'y':
                # Breaks out of the prompt loop and play another round of RPS.
                break
            else:
                print("Invalid input!\n")
                # Keep going in the 'replay' prompt loop until valid input.
                continue