python中的列表索引错误，tic tac toe游戏

我正在做本页的python课程。 我已经创建了tic-tac-toe，我自己输入了上面站点的所有代码

有时代码工作正常。有时我会犯这个错误，游戏就会崩溃

Traceback (most recent call last):
  File "E:\Python\tictac.py", line 139, in <module>
    makeMove(theBoard, computerLetter, move)
  File "E:\Python\tictac.py", line 40, in makeMove
    board[move] = letter
TypeError: list indices must be integers, not NoneType

您应该转换：

def chooseRandomMoveFromList(board, moveList):
    possibleMoves = []
    for i in moveList:
        if isSpaceFree(board, i):
            possibleMoves.append(i)

        if len(possibleMoves) != 0:
            return random.choice(possibleMoves)
        else:
            return None

到

问题是，由于压痕，您无法计算所有自由位置。相反，如果第一个候选职位是免费的，则只检查它，如果不是免费的，则不返回任何内容

def chooseRandomMoveFromList(board, moveList):
    possibleMoves = []
    for i in moveList:
        if isSpaceFree(board, i):
            possibleMoves.append(i)

        if len(possibleMoves) != 0:
            return random.choice(possibleMoves)
        else:
            return None

def chooseRandomMoveFromList(board, moveList):
    possibleMoves = []
    for i in moveList:
        if isSpaceFree(board, i):
            possibleMoves.append(i)

    if len(possibleMoves) != 0:
        return random.choice(possibleMoves)
    else:
        return None