Python实现的井字棋（Tic Tac Toe）游戏示例

本文实例讲述了Python实现的井字棋（Tic Tac Toe）游戏。分享给大家供大家参考，具体如下：

说明

用python实现了井字棋，整个框架是本人自己构思的，自认为比较满意。另外，90％+的代码也是本人逐字逐句敲的。

minimax算法还没完全理解，所以参考了这里的代码，并作了修改。

特点

可以选择人人、人机、机人、机机四种对战模式之一
电脑玩家的AI使用了minimax算法，带apha-beta剪枝
电脑玩家在思考时，时时刻刻都有一个“假想敌”。以便使得minimax算法运转起来

代码

#作者：hhh5460
#时间：2017年6月26日
# 棋盘
class Board(object):
def __init__(self):
 #self._board = '-'*9 # 坑！！
 self._board = ['-' for _ in range(9)]
 self._history = [] # 棋谱
# 按指定动作，放入棋子
def _move(self, action, take):
 if self._board[action] == '-':
  self._board[action] = take
  self._history.append((action, take)) # 加入棋谱
# 撤销动作，拿走棋子
def _unmove(self, action):
 self._board[action] = '-'
 self._history.pop()
# 棋盘快照
def get_board_snapshot(self):
 return self._board[:]
# 取棋盘上的合法走法
def get_legal_actions(self):
 actions = []
 for i in range(9):
  if self._board[i] == '-':
   actions.append(i)
 return actions
# 判断走法是否合法
def is_legal_action(self, action):
 return self._board[action] == '-'
# 终止检测
def teminate(self):
 board = self._board
 lines = [board[0:3], board[3:6], board[6:9], board[0::3], board[1::3], board[2::3], board[0::4], board[2:7:2]]
 if ['X']*3 in lines or ['O']*3 in lines or '-' not in board:
  return True
 else:
  return False
# 胜负检查
def get_winner(self):
 board = self._board
 lines = [board[0:3], board[3:6], board[6:9], board[0::3], board[1::3], board[2::3], board[0::4], board[2:7:2]]
 if ['X']*3 in lines:
  return 0
 elif ['O']*3 in lines:
  return 1
 else:
  return 2
# 打印棋盘
def print_b(self):
 board = self._board
 for i in range(len(board)):
  print(board[i], end='')
  if (i+1)％3 == 0:
   print()
# 打印棋谱
def print_history(self):
 print(self._history)
# 玩家
class Player(object):
'''
玩家只做两件事：思考、落子
 1. 思考 --> 得到走法
 2. 落子 --> 执行走法，改变棋盘
'''
def __init__(self, take='X'): # 默认执的棋子为 take = 'X'
 self.take=take
def think(self, board):
 pass
def move(self, board, action):
 board._move(action, self.take)
# 人类玩家
class HumanPlayer(Player):
def __init__(self, take):
 super().__init__(take)
def think(self, board):
 while True:
  action = input('Please input a num in 0-8:')
  if len(action)==1 and action in '012345678' and board.is_legal_action(int(action)):
   return int(action)
# 电脑玩家
class AIPlayer(Player):
def __init__(self, take):
 super().__init__(take)
def think(self, board):
 print('AI is thinking ...')
 take = ['X','O'][self.take=='X']
 player = AIPlayer(take)  # 假想敌！！！
 _, action = self.minimax(board, player)
 #print('OK')
 return action
# 极大极小法搜索，α-β剪枝
def minimax(self, board, player, depth=0) :
 '''参考：https://stackoverflow.com/questions/44089757/minimax-algorithm-for-tic-tac-toe-python'''
 if self.take == "O":
  bestVal = -10
 else:
  bestVal = 10
 if board.teminate() :
  if board.get_winner() == 0 :
   return -10 + depth, None
  elif board.get_winner() == 1 :
   return 10 - depth, None
  elif board.get_winner() == 2 :
   return 0, None
 for action in board.get_legal_actions() : # 遍历合法走法
  board._move(action, self.take)
  val, _ = player.minimax(board, self, depth+1) # 切换到 假想敌！！！
  board._unmove(action) # 撤销走法，回溯
  if self.take == "O" :
   if val > bestVal:
    bestVal, bestAction = val, action
  else :
   if val < bestVal:
    bestVal, bestAction = val, action
 return bestVal, bestAction
# 游戏
class Game(object):
def __init__(self):
 self.board = Board()
 self.current_player = None
# 生成玩家
def mk_player(self, p, take='X'): # p in [0,1]
 if p==0:
  return HumanPlayer(take)
 else:
  return AIPlayer(take)
# 切换玩家
def switch_player(self, player1, player2):
 if self.current_player is None:
  return player1
 else:
  return [player1, player2][self.current_player == player1]
# 打印赢家
def print_winner(self, winner): # winner in [0,1,2]
 print(['Winner is player1','Winner is player2','Draw'][winner])
# 运行游戏
def run(self):
 ps = input("Please select two player's type:\n\t0.Human\n\t1.AI\nSuch as:0 0\n")
 p1, p2 = [int(p) for p in ps.split(' ')]
 player1, player2 = self.mk_player(p1, 'X'), self.mk_player(p2, 'O') # 先手执X，后手执O
 print('\nGame start!\n')
 self.board.print_b() # 显示棋盘
 while True:
  self.current_player = self.switch_player(player1, player2) # 切换当前玩家
  action = self.current_player.think(self.board) # 当前玩家对棋盘进行思考后，得到招法
  self.current_player.move(self.board, action) # 当前玩家执行招法，改变棋盘
  self.board.print_b() # 显示当前棋盘
  if self.board.teminate(): # 根据当前棋盘，判断棋局是否终止
   winner = self.board.get_winner() # 得到赢家 0,1,2
   break
 self.print_winner(winner)
 print('Game over!')
 self.board.print_history()
if __name__ == '__main__':
Game().run()

下图是人人对战的结果

希望本文所述对大家Python程序设计有所帮助。

来源：http://www.cnblogs.com/hhh5460/p/7082112.html