Rock Paper Scissors, written in Python

rock_paper_scissors.py

import random

print("Welcome to a game of Rock Paper Scissors!")

while True:

    # ask whether to play rock, paper or scissors
    user_choice = input("Choose one (rock, paper, scissors): ").strip().lower()

    # validate input
    if user_choice == "":
        print("You need to choose one!")
    elif user_choice not in ("rock", "paper", "scissors"):
        print("That's not a valid option!")
    else:
        break

# let the computer decide
computer_choice = random.choice(("rock", "paper", "scissors"))

# compare with what the computer chooses
if user_choice == computer_choice:
    print("It's a draw!")
else:
    player_win_combinations = (("rock", "scissors"), ("paper", "rock"), ("scissors", "paper"))

    if (user_choice, computer_choice) in player_win_combinations:
        print(f"You won against computer's {computer_choice}!")
    else:
        print(f"You lost against computer's {computer_choice}!")