Want to improve your Python skills while building a fun project? This tutorial will guide you through creating a Rock Paper Scissors game using Python!
By the end, you’ll have a working game where the user plays against the computer in an interactive, score-tracking version of Rock Paper Scissors.
This beginner-friendly project covers essential programming concepts, including:
- Using the random module to simulate a computer opponent
- Handling user input validation using regular expressions
- Working with loops and conditional statements
- Keeping track of the score and allowing replay
Let’s dive in!
Step 1: Setting Up the Project
Before we start coding, let’s set up our Python project:
1. Make sure Python is installed on your computer. If not, download it from the official Python website.
2. Open your favorite code editor or IDE.
3. Create a new Python file, for example, rock_paper_scissors.py.
Great, now, let's dive head first into our Python editor to get this build started.
Step 2: Understanding How the Game Works
The Rock Paper Scissors game follows these rules:
- The user chooses Rock (R), Paper (P), or Scissors (S).
- The computer randomly selects one of the three options.
- The game determines the winner based on these conditions:
- Rock beats Scissors 🪨✂️
- Scissors beats Paper ✂️📄
- Paper beats Rock 📄🪨
- The game tracks the score and asks if the user wants to play again.
Now, let’s start coding in Python!
Step 3: Importing Required Modules
We need three Python modules for this project:
import random # For generating random choicesimport os # To clear the screen between roundsimport re # For validating user inputWhy Do We Use These Modules?
random: Python random allows the computer to randomly select Rock, Paper, or Scissors.os: Clears the terminal screen after each round for better readability.re: Helps us validate user input using regular expressions (regex).
Step 4: Asking the User If They Want to Play Again
At the end of each round, we’ll ask the user if they want to continue playing.
def check_play_status(): valid_responses = ['yes', 'no', 'y'] while True: try: response = input('Do you wish to play again? (Yes or No): ') if response.lower() not in valid_responses: raise ValueError('Yes or No only') if response.lower() in ['yes', 'y']: return True else: os.system('cls' if os.name == 'nt' else 'clear') print('Thanks for playing!') exit() except ValueError as err: print(err)How It Works
- A list of valid responses (
yes,no,y) ensures proper input validation. - If the user enters "yes" or "y", the game continues.
- If they type "no", we clear the screen, display a thank-you message, and exit using
exit(). - If they enter anything else, the function keeps asking until they provide a valid response.
Step 5: Writing the Core Game Logic
Now, let’s write the function that runs the Rock Paper Scissors game.
def play_rps(): user_score = 0 computer_score = 0 play = True while play: os.system('cls' if os.name == 'nt' else 'clear') print('') print('Rock, Paper, Scissors - Shoot!') user_choice = input('Choose your weapon [R]ock, [P]aper, or [S]cissors: ') # Validate input using regex if not re.match("^[RrPpSs]$", user_choice): print('Invalid choice! Please choose: [R]ock, [P]aper, or [S]cissors.') continue print(f'You chose: {user_choice.upper()}') choices = ['R', 'P', 'S'] opp_choice = random.choice(choices) print(f'I chose: {opp_choice}') # Determine the winner if opp_choice == user_choice.upper(): print('It\'s a Tie!') elif (opp_choice == 'R' and user_choice.upper() == 'S') or \ (opp_choice == 'S' and user_choice.upper() == 'P') or \ (opp_choice == 'P' and user_choice.upper() == 'R'): print(f'{opp_choice} beats {user_choice.upper()}, I win!') computer_score += 1 else: print(f'{user_choice.upper()} beats {opp_choice}, You win!') user_score += 1 print(f'Score - You: {user_score}, Computer: {computer_score}') play = check_play_status()How It Works
- The game runs in a loop (
while play:) until the player decides to stop. - The screen clears at the beginning of each round for a clean look.
- Regular expressions (
re.match()) ensure valid input (only R, P, or S). - The computer randomly picks Rock, Paper, or Scissors.
- The game uses if-elif-else conditions to determine the winner and update scores.
- The user can play again or exit after each round.
The core functionality of our Rock Paper Scissors game is handled in the play_rps() function.
It does three main things:
- Takes user input and validates it.
- Uses the random module to let the computer make a choice.
- Compares choices using if-elif-else statements to determine the winner.
Using a while Loop for Continuous Gameplay
The game runs in a while loop to let the user play multiple rounds until they choose to quit.
while play:Why Use a while Loop?
- Keeps the game running until the player exits.
- Allows us to reset the game variables and restart fresh for a new round.
- Improves user experience by making the game interactive.
When the user decides to quit, we set play = False, breaking out of the loop.
Clearing the Screen for a Better User Experience
os.system('cls' if os.name == 'nt' else 'clear')Why Do We Use This?
- This command clears the terminal screen between rounds, so old outputs don’t clutter the interface.
clsis used for Windows, whileclearis used for Linux/macOS.- The
os.namecheck ensures that the correct command is used based on the operating system.
Taking and Validating User Input with input() and re.match()
user_choice = input('Choose your weapon [R]ock, [P]aper, or [S]cissors: ')if not re.match("^[RrPpSs]$", user_choice): print('Invalid choice! Please choose: [R]ock, [P]aper, or [S]cissors.') continueWhy Use re.match()?
- Ensures the user input is valid (only "R", "P", or "S").
- Uses regular expressions (regex) to check if the input is a single character and belongs to the allowed choices.
- If the user enters anything invalid, the game displays an error message and asks them to try again.
Using random.choice() for Computer’s Move
choices = ['R', 'P', 'S']opp_choice = random.choice(choices)Why Use random.choice()?
- Generates a truly random selection between Rock, Paper, and Scissors.
- Eliminates predictability, making the game more realistic.
Instead of writing multiple conditions, random.choice() simplifies the code by picking from a list.
Using if-elif-else to Determine the Winner
if opp_choice == user_choice.upper(): print('It\'s a Tie!')elif (opp_choice == 'R' and user_choice.upper() == 'S') or \ (opp_choice == 'S' and user_choice.upper() == 'P') or \ (opp_choice == 'P' and user_choice.upper() == 'R'): print(f'{opp_choice} beats {user_choice.upper()}, I win!') computer_score += 1else: print(f'{user_choice.upper()} beats {opp_choice}, You win!') user_score += 1How Does This Work?
First, we check for a tie:
- If both choices are the same (
opp_choice == user_choice.upper()), we print"It's a Tie!".
Then, we check for a computer win:
- We list out all losing conditions for the player using logical OR (
or).
Else, the player wins:
- If neither of the above conditions are met, the user wins by default.
Why Use or Statements?
- Easier to read and modify instead of multiple if conditions.
- Explicitly states all losing conditions in one line.
Keeping Score Between Rounds
print(f'Score - You: {user_score}, Computer: {computer_score}')Each time a player wins, we increment their score.
computer_score += 1→ Adds 1 to the computer’s score if the player loses.user_score += 1→ Adds 1 to the user’s score if they win.
This f-string ensures that the score is updated correctly between rounds.
Step 6: Running the Game
Finally, we use this simple but powerful line to control when the game starts:
if __name__ == '__main__': play_rps()Why Is This Needed?
Python sets a special variable called __name__ when a script is run.
- If the script is executed directly,
__name__is set to"__main__", soplay_rps()runs. - If the script is imported as a module,
__name__is set to the module’s name, andplay_rps()does not run automatically.
Why Is This Best Practice?
- Allows the game to run only when intended.
- Prevents automatic execution if imported into another script.
- Makes the code modular and reusable for future projects.
Final Code: Rock Paper Scissors Game
import randomimport osimport redef check_play_status(): valid_responses = ['yes', 'no', 'y'] while True: try: response = input('Do you wish to play again? (Yes or No): ') if response.lower() not in valid_responses: raise ValueError('Yes or No only') if response.lower() in ['yes', 'y']: return True else: os.system('cls' if os.name == 'nt' else 'clear') print('Thanks for playing!') exit() except ValueError as err: print(err)def play_rps(): user_score = 0 computer_score = 0 play = True while play: os.system('cls' if os.name == 'nt' else 'clear') print('\nRock, Paper, Scissors - Shoot!') user_choice = input('Choose your weapon [R]ock, [P]aper, or [S]cissors: ') if not re.match("^[RrPpSs]$", user_choice): print('Invalid choice! Try again.') continue print(f'You chose: {user_choice.upper()}') choices = ['R', 'P', 'S'] opp_choice = random.choice(choices) print(f'I chose: {opp_choice}') if opp_choice == user_choice.upper(): print('It\'s a Tie!') elif (opp_choice == 'R' and user_choice.upper() == 'S') or \ (opp_choice == 'S' and user_choice.upper() == 'P') or \ (opp_choice == 'P' and user_choice.upper() == 'R'): print(f'{opp_choice} beats {user_choice.upper()}, I win!') computer_score += 1 else: print(f'{user_choice.upper()} beats {opp_choice}, You win!') user_score += 1 print(f'Score - You: {user_score}, Computer: {computer_score}') play = check_play_status()if __name__ == '__main__': play_rps()Wrapping Up
Congratulations! You’ve built a complete Rock Paper Scissors game in Python!
This project helped you practice:
- Using Python’s random module to make decisions
- Loops (while) to keep the game running
- Handling user input validation (re.match())
- Using if-elif-else conditions to determine winners
- Keeping track of scores dynamically
- Following best practices (if __name__ == '__main__')
Next Steps: Enhance Your Game!
- Add an extended best-of-5 mode.
- Include a difficulty setting where the computer picks based on player history.
- Make a graphical version using Tkinter or PyQt.
The best way to learn Python is by building fun projects—so keep experimenting!
