Tic Tac Toe game in Python

tic-tac-toe.py

import re

class TicTacToe:
  def __init__(self, n=3):
    self.n = n
    self.board = [
      ['_' for col in range(n)] 
      for row in range(n)
    ]
    self.teams = ['X', 'O']
    self.winner = ' '

  def __str__(self):
    return '\n'.join([
      ' ' + '|'.join(row) for row in self.board
    ])
  
  def play(self):
    """Begins the game."""
    i = 0
    print('Tic Tac Toe!')
    while (not self.has_winner()) and (not self.is_filled()):
      print('-------------')
      print(self)
      team = self.teams[i % 2]
      row, col = self.get_move(team)
      self.make_move(team, row, col)
      i += 1
    print('-------------')
    print(self)
    if self.has_winner():
      print('Team {0} has won!'.format(self.winner))
    else:
      print('It is a draw!')

  def get_move(self, team):
    """Retrieves move from user."""
    move = ''
    while not self.is_valid(move):
      move = raw_input("{0}'s turn: ".format(team))
    return self.parse_move(move)

  def is_valid(self, move):
    """Returns True if move is valid, False otherwise."""
    pattern = re.compile('^\d+,\d+$')
    if pattern.match(str(move)):
      row, col = self.parse_move(move)
      if (0 <= row < self.n) and (0 <= col < self.n):
        # move is valid if its spot on the board is blank
        return self.board[row][col] == '_'
    else:
      return False

  def parse_move(self, move):
    """Parses move into a (row, col) after it has been validated"""
    coordinates = [int(n) for n in move.split(',')]
    return coordinates[0], coordinates[1]
    
  def make_move(self, team, row, col):
    """Places the given team's symbol at (row, col)"""
    self.board[row][col] = team
    self.check(team, row, col)

  def check(self, team, row, col):
    """Checks the row, column, and diagonals of the cell at (row, col)
       to see if their cells are each the same as the given team."""
    # row
    if all([cell == team for cell in self.board[row]]):
      self.winner = team

    # column
    if all([self.board[i][col] == team for i in range(self.n)]):
      self.winner = team

    # diagonal A: top-left to bottom-right
    if row == col:
      if all([self.board[i][j] == team for i, j in enumerate(range(self.n))]):
        self.winner = team

    # diagonal B: top-right to bottom-left
    if row == self.n - col - 1:
      if all([self.board[i][self.n - j - 1] == team for i, j in enumerate(range(self.n))]):
        self.winner = team

  def is_filled(self):
    """Returns True if no cell on the board is blank, False otherwise."""
    for row in self.board:
      for cell in row:
        if cell == '_':
          return False
    return True

  def has_winner(self):
    """Returns True if a winner has been determined, False otherwise"""
    return self.winner in self.teams


tictactoe = TicTacToe()
tictactoe.play()