Python CS50AI Tictactoe函数的一个参数为None，原因是什么？

我正在尝试为CS50AI的第一个任务创建一个tictactoe AI。我得到了你将在下面看到的错误。这意味着结果函数中的操作以某种方式为

None

。但问题是我只需点击一下鼠标，怎么可能是N one

my函数给出以下错误：

    Traceback (most recent call last):
  File "c:\Users\ahmet\Desktop\tictactoe\runner.py", line 116, in <module>
    board = ttt.result(board, move)
  File "c:\Users\ahmet\Desktop\tictactoe\tictactoe.py", line 69, in result
    raise Exception("Invalid action")
Exception: Invalid action

---

我找到了答案：这是因为我的

minimax

函数。除非有一个胜利的举动，否则它将一无所获。我忘了给它的其余部分编码了。谢谢你的帮助。

board=ttt.result（board，move）

显然不是你的代码的一部分，但是

move

已经是

None

，所以问题不在于你共享的代码，而在于你没有共享的代码。。。

"""

Tic Tac Toe Player
"""

import math

X = "X"
O = "O"
EMPTY = None

def initial_state():
    """
    Returns starting state of the board.
    """
    return [[EMPTY, EMPTY, EMPTY],
            [EMPTY, EMPTY, EMPTY],
            [EMPTY, EMPTY, EMPTY]]
            
def initial_stateh():
    
    return [[X, X, X],
            [EMPTY, EMPTY, EMPTY],
            [EMPTY, EMPTY, EMPTY]]

def initial_statetie():
    
    

    return [[O, X, O],
            [X, O, X],
            [X, X, O]]

def initial_stateboş():
     
    return [[EMPTY, O, O],
            [X, O, EMPTY],
            [X, X, EMPTY]]



def player(board):
    numx = 0
    numo = 0
    for i in range(3):
        for j in range(3):
            if board[i][j] == X:
                numx = numx + 1
            if board[i][j] == O:
                numo = numo + 1
    
    if numx == numo:
        return X
    elif numx > numo:
        return O
    
def actions(board):
    possiblemoves = set()
    for i in range(3):
        for j in range(3):
            if board[i][j] == EMPTY:
                possiblemoves.add((i,j))
    return possiblemoves

def result(board, action):
    """
    Returns the board that results from making move (i, j) on the board.
    """
    if action is None:
        raise Exception("Invalid action")
    
    copyboard = [row[:] for row in board]

    if copyboard[ action[0] ][ action[1] ] is EMPTY:
        
        #print(action[0],action[1])
        
        copyboard[ action[0] ][ action[1] ] = player(board)
        return copyboard

    else:
        raise Exception("Move is not possible")

def horizontal(board):
    for x in range(3):
        if (board[x][0] == board[x][1] and board[x][1] == board[x][2]) and board[x][0] != None:
            pl = board[x][0]
            return pl
    
        return None

def vertical(board):
    for y in range(3):
        if (board[0][y] == board[1][y] and board[1][y] == board[2][y]) and board[1][y] != None:
            pl = board[1][y]
            return pl
    return None

def diagonally(board):
    if (board[0][0] == board[1][1] and board[1][1]==board[2][2]) and board[0][0] != None:
        return board[0][0]
    if (board[0][2] == board[1][1] and board[1][1]==board[2][0]) and board[0][2] != None:
        return board[0][2]
    else:
        return None


def winner(board):
    """
    Returns the winner of the game, if there is one.
    """
    if vertical(board) != None :
        return vertical(board)
    if horizontal(board) != None :
        return horizontal(board)
    if diagonally(board) != None :
        return diagonally(board)
    else:
        return None
def arethereanyspace(board):
    space = 0
    for row in board:
        for item in row:
            if item == None:
                space +=1


    else:
        return space

def tie(board):
    if winner(board) == None and arethereanyspace(board) == None:
        return True
    else:
        return False
def terminal(board):
    """
    Returns True if game is over, False otherwise.
    """
    if tie(board) == True :
        return True
    if winner(board) != None:
        return True
    else:
        return False


def utility(board):
    """
    Returns 1 if X has won the game, -1 if O has won, 0 otherwise.
    """
    if winner(board) == X:
        return 1
    if winner(board) == O:
        return -1
    if tie(board):
        return 0


def minimax(board):
    """
    Returns the optimal action for the current player on the board.
    """
    if terminal(board) == True: #if the game has ended
        return None

    for move in actions(board): 
        if winner(result(board, move)) != None:#if the move is a winning move, do it!
            return move
        i = move[0]
        j = move[1]
        if j+1 <= 2 and board[i][j+1] == player(board): #check horizontal
            return move
        if j-1 >= 0 and board[i][j-1] == player(board): #check horizontal
            return move

        if i+1 <= 2 and board[i+1][j] == player(board): #check vertical
            return move
        if i-1 >= 0 and board[i-1][j] == player(board): #check vertical
            return move

        if (j+1<=2) and (i+1<= 2) and board[i+1][j+1] == player(board): #checking the diag
            return move
        if (i-1 >= 0) and (j-1 >= 0) and board[i-1][j-1] == player(board): #checking the diag
            return move

        if (i-1 >= 0) and (j+1 <= 2) and board[i-1][j+1] == player(board):
            return move
        if (i+1 <= 2) and (j-1 >= 0) and board[i+1][j-1] == player(board):
            return move