Creating a Tic Tac Toe game with Python

In this post we are going to create a Tic Tac Toe game using Python. The game will not have a graphical interface, it will be via terminal.

Imports

First, let’s import two libraries that we will use to develop the game: random (to generate random numbers) and tabulate (to create tables).

The random is already a native Python library, so we can import it directly into code. The tabulate library is not native to Python so we need to run the pip install tabulate command to install it.

Now just do the imports as follows:

import random
from tabulate import tabulate

Play function

Our game will run from a function called play. So now we need to define it and then indicate that the game is starting:

def play():
  print("")
  print("============ START ============")

Game options

Now we need to define two variables: options (an array that receives the choice options) and wins (a dictionary that indicates which option wins which)

options = ["rock", "paper", "scissors"]
wins = {
    "rock": "scissors",
    "paper": "rock",
    "scissors": "paper"
}

Get players options

The next step is to receive the players’ choices (user and CPU) and store them in the variables player and cpu.

To receive the user’s choice we will do:

print('''
Choose your weapon:

[0] - {0}
[1] - {1}
[2] - {2}
'''.format(options[0], options[1], options[2]))
  
player = int(input("Choose an option: "))

To receive the “choice” from the CPU, we’ll use the random.randint method to generate a random value between 0 and 2, which are the possible indexes of our options array:

cpu = random.randint(0, 2)

Get result

Now we need to compare the user and CPU choices and store the winner of the match in a result variable. To do this, we will use the if/else condition structure, taking into account that:

1. if user and cpu chose the same option then we don’t have a winner
2. if the user chose a property from the wins dictionary and the CPU chose the value corresponding to that property, then the winner is the user
3. if neither event 1 nor event 2 occurred then the winner is the CPU

Now, just turn these conditions into code:

result = ""

if options[player] == options[cpu]:
  result = "No winners"
elif wins[options[player]] == options[cpu]:
  result = "Player"
else:
  result = "CPU"

Show results

To show the result of the match, we will use the tabulate method that we imported from the tabulate library. For this, first, we need to create an array whose first item will be an array with the header of our table (Player, CPU and Winner) and the second item will be an array with the table data (user option, CPU option and match winner):

resultsTable = [
  ['Player', 'CPU', 'Winner'], 
  [options[player], options[cpu], result], 
]

Finally it is now possible to show the result of the match:

print('''
=========== RESULTS ===========
{0}
'''.format(tabulate(resultsTable, headers='firstrow', tablefmt='grid')))

Play again

To end our game, we can give the user the option to start a new game. For this we will use the following conditions:

1. if the user types 1, a new game will be started
2. if the user types any other value, the game will be finished

print('''
Play again?

[1] - Yes
[ANY] - No
''')

playAgain = input("Choose an option: ")

if playAgain == "1":
  play()

NOTE: the play function is a recursive function, that is, it is a function that calls itself.

Starting the game

Finally, call the play function so that the game starts as soon as the file is executed:

play()

More

• Suggestion for improvement: handle error when user chooses option greater than 2 and less than 0.
• Code: https://colab.research.google.com/drive/1dm-ZPAsBdWAfbTIc1lmFWCbOs12ABd0a?usp=sharing