"TypeError: list indices must be integers or slices, not NoneType" in tictactoe game (Python 3)

Question

我一直在开发 Python 3 中的基本井字棋游戏，其中玩家与 AI 竞争以获胜。第一回合，代码成功执行，没有错误，但之后我得到了前面描述的错误。

我试过将 "board[move] = computer" 更改为 "move = computer"，但这只是跳过了计算机的回合，因为没有填写任何内容。

我期望井字板的输出带有一个新的正方形，其中填充了 "O"。但我收到错误消息“board[move] = computer 类型错误：列表索引必须是整数或切片，而不是 NoneType"

代码如下：

X = "X"
O = "O"
EMPTY = " "
TIE = "TIE"
NUM_SQUARES = 9

def pieces():
    go_first = ask_yes_no("Do you require the first move? (y/n): ")
    if go_first == "y":
        print("\nThen take the first move. You will need it.")
        human = X
        computer = O
    else:
        print("\nYour bravery will be your undoing... I'll go first")
        computer = X
        human = O
    return computer, human

def new_board():
    board = []
    for square in range(NUM_SQUARES):
        board.append(EMPTY)
    return board

def legal_moves(board):
    moves = []
    for square in range(NUM_SQUARES):
        if board[square] == EMPTY:
            moves.append(square)
        return moves

def winner(board):
    WAYS_TO_WIN = ((0, 1, 2),
                  (3, 4, 5),
                  (6, 7, 8),
                  (0, 3, 6),
                  (1, 4, 7),
                  (2, 5, 8),
                  (0, 4, 8),
                  (2, 4, 6))

    for row in WAYS_TO_WIN:
        if board[row[0]] == board[row[1]] == board[row[2]] != EMPTY:
            winner = board[row[0]]
            return winner

    if EMPTY not in board:
        return TIE

    return None


def human_move(board, human):
    legal = legal_moves(board)
    move = None
    while move not in legal:
        move = ask_number("Where will you move? (0 - 8):", 0, 
                           NUM_SQUARES)
        if move not in legal:
            print("\nThat square is already occupied. Choose another.\n")
        print("Fine...")
        return move


def computer_move(board, computer, human):
    board = board[:]

    BEST_MOVES = (4, 0, 2, 6, 8, 1, 3, 5, 7)

    print("I shall take square number", end=" ")

    for move in legal_moves(board):
        board[move] = computer
        if winner(board) == computer:
            print(move)
            return move
        board[move] = EMPTY

    for move in legal_moves(board):
        board[move] = human
        if winner(board) == human:
            print(move)
            return move
        board[move] = EMPTY

    for move in BEST_MOVES:
        if move in legal_moves(board):
            print(move)
            return move

def next_turn(turn):
    if turn == X:
        return O
    else:
        return X


def main():
    computer, human = pieces()
    turn = X
    board = new_board()
    display_board(board)

    while not winner(board):
        if turn == human:
            move = human_move(board, human)
            board[move] = human
        else:
            move = computer_move(board, computer, human)
            board[move] = computer

        display_board(board)
        turn = next_turn(turn)

    the_winner = winner(board)

main()

Answer 1

您的 legal_moves 功能已损坏，因为无论如何它 returns 就在第一个 'sqare' 之后。如果它已经被占用，它 returns 一个空列表。

只需将return一个意图向下移动：

def legal_moves(board):
    moves = []
    for square in range(NUM_SQUARES):
        if board[square] == EMPTY:
            moves.append(square)
    return moves

"TypeError: list indices must be integers or slices, not NoneType" in tictactoe game (Python 3)

"TypeError: list indices must be integers or slices, not NoneType" in tictactoe game (Python 3)

python

typeerror

slice

indices