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Activity 2.8 Rock, Paper, Scissors Game

Introduction

Rock, paper, scissors is a fun game to play between friends. Here is a basic rundown of the rules:

• Choose rock, paper, or scissors
• Paper covers rock
• Rock crushes scissors
• Scissors cuts paper

Skills to Practice

• Writing while loops
• Nesting multiple levels of code blocks

Instructions

Setup

1. Create a new repl.
   1. Select Python for the language.
   2. Name the Repl ”2.8 Rock, Paper, Scissors“.
2. Click Create repl.

Code

import random

wins = 0
losses = 0
current_round = 1
playing = True

print("---ROCK, PAPER, SCISSORS---")
print(" --2020 Terminal Edition--")

"""
This is a multi-line string.
It's not technically a comment, but can be used as such.

1. Set the header: round number, wins, losses
2. Prompt user for player hand
3. Generate a random computer hand
4. Check who won
    i. If same hand - tie
   ii. If player chooses rock
      a. Computer paper - lose
      b. Computer scissors - win
  iii. If player chooses paper
      a. Computer scissors - lose
      b. Computer rock - win
   iv. If player chooses scissors
      a. Computer rock - lose
      b. Computer paper - win
5. Prompt user to play again
"""

while playing:
  print(f"ROUND {current_round}!")
  print(f"W: {wins} - L: {losses}")
  print("Rock, Paper, Scissors?")

  player_hand = input("-> ").lower()
  random_number = random.randint(0, 2)

  if random_number == 0:
    computer_hand = "rock"
  elif random_number == 1:
    computer_hand = "paper"
  else:
    computer_hand = "scissors"


  print(f"Computer chooses {computer_hand}!\n")

  if player_hand == computer_hand:
    print("Tie!")
  elif player_hand == "rock":
    if computer_hand == "paper":
      print("You lose! Paper covers rock!\n")
      losses += 1
    else:
      print("You win! Rock crushes scissors!\n")
      wins += 1
  elif player_hand == "paper":
    if computer_hand == "scissors":
      print("You lose! Scissors cuts paper!\n")
      losses += 1
    else:
      print("You win! Paper covers rock!\n")
      wins += 1
  elif player_hand == "scissors":
    if computer_hand == "rock":
      print("You lose! Rock crushes scissors!\n")
      losses += 1
    else:
      print("You win! Scissors cuts paper!\n")
      wins += 1
  else:
    print("You typed something wrong, dummy...\n")


  # If player says no, set playing to false.
  # This terminates the while loop.
  print("\nPlay again?")
  choice = input("-> ")

  if choice == "no":
    playing = False
  else:
    current_round += 1

  print()

Debug

---ROCK, PAPER, SCISSORS---
 --2020 Terminal Edition--
ROUND 1!
W: 0 - L: 0
Rock, Paper, Scissors?
-> scissors
Computer chooses scissors!

Tie!

Play again?
-> yes
ROUND 2!
W: 0 - L: 0
Rock, Paper, Scissors?
-> paper
Computer chooses scissors!

You lose! Scissors cuts paper!

Play again?
-> no

Tips, Tricks, and Reflection

• You can also try rewrite the code to use compound boolean expressions instead of nested if statements when checking if the player won or lost.
• Try making a two player version of rock, paper, scissors. When player one’s turn is done, you can call the function os.system("clear") to clear the screen, so player two can’t cheat. The system function exists in the os module, which is used to execute terminal commands.

import os

os.system("clear")

• If you want to ascend as a programmer, try upgrading the game to Rock, paper, scissors, lizard, Spock!
• As the complexity of your applications increases, it’s more important than ever to make out the requirements. The multi-line comment in the activity code is a basic, but useful guide to tracking what needs to be implemented in the program.