python - 是否可以将 "zip()"与步骤参数一起使用？

Question

我想使用 zip() 方法在 Python 中提取二维数组的一个非常具体的部分(并避免困惑的 for 循环逻辑)。我想使用 zip 来实现这样的目的:

>>> sub_matrix = list(zip([*grid[0:3]]*3))

# Desired output example (Option 1)
[".","4",".", ".",".","4",".",".","."]

# Desired output example (Option 2)
[[".","4","."],  
[".",".","4"],
[".",".","."]]

我正在 Python 中使用下面的二维数组来解决面试练习问题。

grid = [[".","4",".",".",".",".",".",".","."],
    [".",".","4",".",".",".",".",".","."],
    [".",".",".","1",".",".","7",".","."],
    [".",".",".",".",".",".",".",".","."],
    [".",".",".","3",".",".",".","6","."],
    [".",".",".",".",".","6",".","9","."],
    [".",".",".",".","1",".",".",".","."],
    [".",".",".",".",".",".","2",".","."],
    [".",".",".","8",".",".",".",".","."]]

解决该问题的一部分涉及确保数独游戏中的每个 3 x 3“区域”包含合法值。我想使用 zip() 快速提取矩阵的 3 x 3 部分。例如，左上区域会导致测试失败，因为它包含两次 4。

我知道我可以对网格进行子集化以获得前三行，如下所示:

    >>> sub_grid = grid[0:3]
    >>> print(sub_grid)
    [['.', '4', '.', '.', '.', '.', '.', '.', '.'], 
    ['.', '.', '4', '.', '.', '.', '.', '.', '.'], 
    ['.', '.', '.', '1', '.', '.', '7', '.', '.']]

我稍微修改了打印以使其明显，但在这一点上，我想使用 3 的“步长”压缩三个数组，以便每个新数组将从之前的每个数组中压缩 3 个值继续下一个。

在Python3 docs on zip有一段关于我认为如何做到这一点的摘录，但我无法获得所需的输出。

The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n).

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非常感谢任何帮助。谢谢。

Answer 1

没有 zipper 但是 [row[:3] for row in grid[:3]]