Create a rock, paper, scissors game

In this exercise, you build a rock, paper, scissors game in Python. The player types their choice, the computer picks one at random, and your program uses conditional logic to decide who wins. You practice using comparison operators, if/elif/else statements, and logical operators (and, or, not).

This exercise takes approximately 30 minutes.

Set up your workspace

You’ll write and run your code in Visual Studio Code.

Open Visual Studio Code.
Select File > Open Folder, create a new folder called rock-paper-scissors somewhere on your machine, and open it.
In the Explorer panel, select the New File icon and name the file game.py.
Make sure your Python environment is active. You should see a Python version displayed in the bottom status bar. If you see a warning, select it and choose your installed Python interpreter.

Set up your starter code

Before writing any logic, you’ll paste a set of guiding comments into game.py. Because part of this program uses an if/else block, the starter code includes that structure with comment placeholders inside each branch — so you always know exactly where to add each piece of code.

Copy the following code and paste it into game.py:

 import random

 # Display the game title

 # Get and display the player's choice

 # Check if the player's choice is invalid

     # Display an invalid input message
    
 # Play the game if the player's choice is valid

     # Generate the computer's choice

     # Determine the winner

Note: Be sure to maintain the correct indentation levels.

Display the game title

Beneath the # Display the game title comment, add the following lines:
```
 print("Rock, Paper, Scissors!")
 print("-" * 23)
```
Select the ▶ Run Python File button in the top-right corner, or open the terminal (Terminal > New Terminal) and run:
```
 python game.py
```

Verify the output:

 Rock, Paper, Scissors!
 -----------------------

Get the player’s choice

Beneath the # Get and display the player's choice comment, add the following lines:
```
 player = input("Enter your choice (rock, paper, scissors): ").lower()
 print(f"You chose: {player}")
```
The .lower() method converts whatever the player types to lowercase, so Rock, ROCK, and rock are all treated the same way.

Run the program, type a choice when prompted, and verify the output:

 Rock, Paper, Scissors!
 -----------------------
 Enter your choice (rock, paper, scissors): Rock
 You chose: rock

Validate the player’s input

Now you’ll replace the placeholder if condition with the real validation check. You’ll use comparison operators and the and logical operator to confirm the player entered a valid choice.

Beneath the # Check if the player's choice is invalid comment, add the following line:
```
 if player != "rock" and player != "paper" and player != "scissors":
```
The and operator ensures the error message only shows if the input matches none of the valid options.
Beneath the # Display an invalid input message comment, add:
```
 print("Invalid choice. Please enter rock, paper, or scissors.")
```
Be sure to maintain the correct indentation levels beneath the if statement.

Run the program and test it with an invalid entry such as lizard:

 Enter your choice (rock, paper, scissors): lizard
 You chose: lizard
 Invalid choice. Please enter rock, paper, or scissors.

Run it again with a valid choice to confirm no error appears.

Generate the computer’s choice

The computer needs to pick at random. Python includes a built-in random module with a choice() function that selects a random item from a list — that import random line at the top of your file loads it.

First, add an else block beneath the comment # Play the game if the player's choice is valid.
```
 else:
```
This ensures the computer only picks a choice if the player entered a valid one.
Beneath the # Generate the computer's choice comment (inside the else block), add the following lines:
```
 computer = random.choice(["rock", "paper", "scissors"])
 print(f"Computer chose: {computer}")
```
Be sure to maintain the correct indentation levels beneath the else statement.
Run the program a few times with a valid choice and observe that the computer’s choice changes each time.

Determine the winner

Now you’ll add the game logic inside the else block. You’ll use if/elif/else with the == comparison operator and and to check every winning condition.

Beneath the # Determine the winner comment (inside the else block), add the following lines:

 if player == computer:
     print("It's a tie!")
 elif player == "rock" and computer == "scissors":
     print("You win! Rock crushes scissors.")
 elif player == "paper" and computer == "rock":
     print("You win! Paper covers rock.")
 elif player == "scissors" and computer == "paper":
     print("You win! Scissors cuts paper.")
 else:
     print(f"Computer wins! {computer.capitalize()} beats {player}.")

Each elif uses and to check two conditions at once: both the player’s choice and the computer’s choice must match for that branch to run.

Your complete game.py should now look like this:

 import random

 # Display the game title
 print("Rock, Paper, Scissors!")
 print("-" * 23)

 # Get and display the player's choice
 player = input("Enter your choice (rock, paper, scissors): ").lower()
 print(f"You chose: {player}")

 # Check if the player's choice is invalid
 if player != "rock" and player != "paper" and player != "scissors":
     # Display an invalid input message
     print("Invalid choice. Please enter rock, paper, or scissors.")
        
 # Play the game if the player's choice is valid
 else:
     # Generate the computer's choice
     computer = random.choice(["rock", "paper", "scissors"])
     print(f"Computer chose: {computer}")

     # Determine the winner
     if player == computer:
         print("It's a tie!")
     elif player == "rock" and computer == "scissors":
         print("You win! Rock crushes scissors.")
     elif player == "paper" and computer == "rock":
         print("You win! Paper covers rock.")
     elif player == "scissors" and computer == "paper":
         print("You win! Scissors cuts paper.")
     else:
         print(f"Computer wins! {computer.capitalize()} beats {player}.")

Run the program several times to test each possible outcome — win, lose, and tie.

 Rock, Paper, Scissors!
 -----------------------
 Enter your choice (rock, paper, scissors): rock
 You chose: rock
 Computer chose: scissors
 You win! Rock crushes scissors.

Extend with GitHub Copilot

Now that the game is working, use GitHub Copilot to extend it. Open the Copilot Chat panel in VS Code (Ctrl+Alt+I) and try the following prompts.

Explore other ways to write conditions

“In Python, what is the ‘in’ operator, and how could I use it to simplify checking if a player’s input is valid?”

Python has a cleaner alternative to chaining != with and. Ask the AI to explain it and try rewriting your input validation line.

Understand short-circuit evaluation

“What is short-circuit evaluation in Python’s ‘and’ and ‘or’ operators? Can you show me an example?”

This is an important behavior to understand when your conditions involve function calls or expressions that could raise errors.

Think about edge cases

“What are some edge cases I should test in a rock, paper, scissors game? How could conditional logic handle them?”

Use the AI’s answer to think critically about inputs your current program doesn’t handle — then decide which ones are worth adding.