A Tic Tac Toe Game

tictactoe.py

def draw_board(board):
     ''' Prints the board in its current stage
         "board" is a list of 9 elements
     '''
     # Prints the board as it is described at the current stage
     # "board" is a list of 9 elements
     print('     |     |     ')
     print('  ' + str(board[0]) + '  |  ' + str(board[1]) + '  |  ' + str(board[2]))
     print('     |     |     ')
     print('-----------------')
     print('     |     |     ')
     print('  ' + str(board[3]) + '  |  ' + str(board[4]) + '  |  ' + str(board[5]))
     print('     |     |     ')
     print('-----------------')
     print('     |     |     ')
     print('  ' + str(board[6]) + '  |  ' + str(board[7]) + '  |  ' + str(board[8]))
     print('     |     |     ')
     print('\n')


def play_board(pos, player, piece):
    ''' Puts a piece from the player on a specific position.
        Checks to see if the position is filled and valid
    '''
    board = board_contents("status")    
    valid = board[pos-1] == ' '

    while not valid:
        if (board[pos-1] == "X") or (board[pos-1] == "O"):
            print("Sorry, that spot is already filled. Pick again.")
            pos, piece = pick_position(player, piece)
            break
        elif (board[pos-1] > 9) or (board[pos-1] < 1):
            print("That is not a valid position, please try again.")
            pos, piece = pick_position(player, piece)
            break
        else:
            valid = True
    board = board_contents("play", pos, piece)
    return board


def board_contents(option = "status", pos = -1, piece = "+", board = [' ']*9):
    ''' Fills the board based on the option.
        "positions" shows the numeric selection of each spot
        "blank" shows a blank board to start
        "play" fills the blank board with a symbol at the correct spot
        "status" shows the board at its current status
    '''
    for i in range(9):
        if option == "positions":
            board[i] = i+1 # defines the positions to play
        if option == "blank":
           board[i] = ' '
        elif option == "play":
            board[pos-1] = piece
    return board


def play_2players():
    ''' Prompts for two users' names
    '''
    first_player = raw_input("What is the name of the first player? ")
    second_player = raw_input("What is the name of the second player? ")
    return first_player.capitalize(), second_player.capitalize()


def pick_pieces(player):
    ''' Allows the first player to pick a piece to play, X or O
    '''
    pieces = ['X','O']
    valid = False

    while not valid:
        first_piece = raw_input("What piece would %s like to play, X or O? " %player)
        piece1 = first_piece.upper()
        if piece1 in pieces:
            valid = True
            if pieces.index(piece1) == 0:
                piece2 = 'O'
            elif pieces.index(piece1) == 1:
                piece2 = 'X'
        else:
            print("Not a valid piece, please pick between X and O.")
    return piece1, piece2


def pick_position(player, piece):
    ''' Allows a player to pick a specific spot to put the piece
        Reprompts if the spot is not a valid number
    '''
    valid = False

    while not valid:
        try:
            spot = int(raw_input("Pick a spot, %s: " % player))
            if spot in range(1,10):
                valid = True
            else:
                print("Not a valid position, please pick a spot between 1 and 9")
        except ValueError:
            print("That's not a number, please pick a spot between 1 and 9")

    return spot, piece


def check_win(board, player, piece):
    ''' Checks to see if someone has won according to the possible selections
    '''
    wins = [[0,1,2],[3,4,5],[6,7,8], # top, middle, bottom
            [0,3,6],[1,4,7],[2,5,8], # left, center, right
            [0,4,8],[2,4,6]] # diagonals
    for win in wins:
        if board[win[0]] == piece and board[win[1]] == piece and board[win[2]] == piece:
            print("%s wins! Congratulations %s!") % (piece, player)
            return True
    return False


def play(p1, p1pick, p2, p2pick):
    ''' Plays the game in turns between each player until a player has won
        or the board is full
        Counts the number of rounds of play
        Stops the loop if there is a win
    '''
    results = []
    round = 0
    win = False

    while not win:
        print("Round #%d")%(round+1)
        spot1, p1pick = pick_position(p1, p1pick)
        results = play_board(spot1, p1, p1pick)
        draw_board(results)
        win = check_win(results, p1, p1pick)
        if win or ' ' not in results:
            print("Game over!")
            break

        spot2, p2pick = pick_position(p2, p2pick)
        results = play_board(spot2, p2, p2pick)
        draw_board(results)
        win = check_win(results, p2, p2pick)

        round += 1


def start_game():
    ''' Starts the game with asking for player names, pieces, and displays board spots
    '''
    print("Welcome! Let's play Tic Tac Toe!")
    p1, p2 = play_2players()
    p1pick, p2pick = pick_pieces(p1)

    print("Okay, %s will play %s and %s will play %s") %(p1, p1pick, p2, p2pick)
    print("To select a spot, please refer to the board positions below.")
    draw_board(board_contents("positions"))

    print("Let's start the game!")
    draw_board(board_contents("blank"))

    play(p1, p1pick, p2, p2pick)

### PLAY GAME

start_game()