Python Tic Tac Toe with Functions

[jorisnl]

Hi all,

I have written a Python Tic Tac Toe game with functions for 2 players on a shared keyboard. I am interested in feedback. It works well, but I am interested in proper scoping of variables ? Have I used functions in a correct way and anything else is highly appreciated. I am learning how to code, however I want to do it in the correct way. I am not up to classes yet. That will be my next project.

Thank you

Joris

#PseudoCode

# Display welcome and instructions 
# Display board 
# Who gets X or O ?
# While no one has won and it isn't a tie loop 
    # get player's move X or O
    # Update the board with the new move 
    # and check legal move, so move that hasn't been taken
    #Switch Turns into X or O
#Congratulate Winner X or O or say it's a Tie

def display_welcome():
    """Display Welcome to Tic Tac Toe """
    print(
        """
        Hi and welcome to this Tic Tac Toe game_board.
        You can win by haveing three X or 3 O in a row.
        This can be horizontal, vertical or diagonal
    
       """
    )

def display_board(game_board):
    """display the board"""
    for x in range(3):
        print("+---+---+---+" )
        for y in range(3):
            print("|", game_board[x*3+y], end = " ")
        print("|")
    print("+---+---+---+" )

def determine_pieces():
    """Determine who gets X or O"""
    answer = None
    answer = input("Do you wish to start with X or O ").upper()
    while not answer in ['X','O']:
        answer = input("Sorry this needs to be X or O ").upper()
    return answer

def determine_winner(game_board):
    """check if there is a win, draw"""
    # check rows
    for i in range(3):
        if game_board[i*3] == game_board[i*3+1] == game_board[i*3+2] and game_board[i*3] in ('X', 'O'):
            return game_board[i*3]
    # check columns
    for i in range(3):
        if game_board[i] == game_board[i+3] == game_board[i+6] and game_board[i] in ('X', 'O'):
            return game_board[i]
    # check diagonals
    if game_board[0] == game_board[4] == game_board[8] and game_board[0] in ('X', 'O'):
        return game_board[0]
    if game_board[2] == game_board[4] == game_board[6] and game_board[2] in ('X', 'O'):
        return game_board[2]
    # check tie
    if all(x in ('X', 'O') for x in game_board):
        return 'Tie'
    # no winner or tie
    return False

def get_move(game_board):
    """ Get the player's move """
    move = int(input(" Please make a move between 1 and 9 "))
    while not legal_move(game_board,move):
        move = int(input( " That move is not legal try again "))
    return move

def legal_move(game_board,player_move):
    """Check if the move is legal"""
    legal = True
    if game_board[player_move -1] in ['X','O']:
        legal = False
    return legal
    
    
def modify_board(game_board,user_piece,move):
    """ Modify the board positions into X or O"""
    game_board[move - 1] = user_piece
    
def switch_turns(user_piece):
    """ Change player's piece into X or O"""
    if user_piece == 'X':
        user_piece = 'O'
    else:
        user_piece = 'X'
    return user_piece 

def win_or_tie(user_piece):
    """ display win for X or O or a tie"""
    if user_piece == "TIE":
        print("This is a TIE, but feel free to play again")
    else:
        print(f"Yes the player with {user_piece} won !!" )


def main():
    """ game_board starting point """
    game_board = [1,2,3,4,5,6,7,8,9]
    player_turn = None
    display_welcome()
    display_board(game_board)
    player_turn = determine_pieces()
    print(f"ok you start with {player_turn}")

    while not determine_winner(game_board):
        player_move = get_move(game_board)
        modify_board(game_board,player_turn,player_move)
        display_board(game_board)
        if not determine_winner(game_board):
            player_turn = switch_turns(player_turn)

    win_or_tie(player_turn)

        
if __name__ == "__main__":
    main()

[gulshan212]

Well, you have covered many basic aspects of Python including exploring new concepts.
Second thing that I want to say that you have also cleary used all function very effectively.
Observer all code deely, nice information at all.
Thanks

[codingismycraft]

1. Move variables that do not change to the global scope as constants.
2. Avoid DRYness (note that you are repeating variables like "+---+---+---+"
3. Removed unused declaration (this is not C), (as example see answer=None)
4. Consider using a class instead of passing the game_board as param
5. If you really need to pass a list (like game_board) consider using a copy of
it (is passed by ref and this can have side effects)
5. Consider a more concise style (see how legal_move can be simplified)
6. Your logic can be simplified
7. Write some unit tests