为多维数组覆盖 setter

Question

我正在尝试覆盖 setter 并装饰它，但不明白它如何用于多维数组。

class Board:
    def __init__(self):
        self.board = []
        for k in range(3):
            self.board.append([0] * 3)

    def __str__(self):
        return '\n'.join([' '.join([str(num) for num in row]) for row in self.board])

    def __repr__(self):
        return self.__str__()

    def __setitem__(self, item, value):
        print(f'setting {item=}\t\t{value=}')
        self.board[item] = value

    def __getitem__(self, item):
        print(f'getting {item=}')
        return self.board[item]

我发现 setter/getter 没有像我预期的那样工作

>>> board = Board()
>>> print(board)
0 0 0
0 0 0
0 0 0
>>> print(board[1][1])
getting item=1
0
>>> board[1][1] = 3
getting item=1

我预计 setter 会在这里工作，但我认为 getter returns 列出并修改该列表的元素。

>>> print(board)
0 0 0
0 3 0
0 0 0
>>> board[0] = [1, 3, 1]
setting item=0      value=[1, 3, 1]
>>> print(board)
1 3 1
0 3 0
0 0 0

Setter 仅当我使用不超过 1 个索引时才有效。

Answer 1

我认为使用 dictionary-of-values 而不是 list-of-lists-of-values[= 做事可能更简单24=]。在这种情况下，您调用 __setitem__() 和 __getitem__() 方法的 item 参数在下面的示例代码中已重命名为 indices，因为它现在是 tuple整数值：(row, col).

class Board: H, W = 3, 3 # Size in rows (height) X columns (width). def __init__(self): self.board = {(row, col): 0 for col in range(self.H) for row in range(self.W)} def __str__(self): return '\n'.join(', '.join(str(self[row, col]) for col in range(self.H)) for row in range(self.W)) __repr__ = __str__ def __setitem__(self, indices, value): self.board[indices] = value def __getitem__(self, indices): return self.board[indices] if __name__ == '__main__': board = Board() print(board) print(f'{board[1, 2]=}') print() board[1, 2] = 3 print(f'{board[1, 2]=}') print(board)

输出：

0, 0, 0 0, 0, 0 0, 0, 0 board[1, 2]=0 board[1, 2]=3 0, 0, 0 0, 0, 3 0, 0, 0

为多维数组覆盖 setter

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