如何用Python旋转由列表构成的棋盘90度？

Hey there! Let's break down how to rotate your 4x4 chessboard 90 degrees (both clockwise and counterclockwise) — it's straightforward with Python's built-in tools, and I'll also show you the manual way to understand the underlying logic.

First, let's recap your current board for reference:

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

1. Rotate 90 Degrees Clockwise #

The easiest way to do this is using reversed() and zip() with a list comprehension. Here's the code:

# Rotate clockwise
rotated_clockwise = [list(row) for row in zip(*reversed(board))]

# Let's print the result to verify
for row in rotated_clockwise:
    print(row)

Output: #

[0, 1, 0, 0]
[3, 0, 0, 0]
[0, 0, 0, 0]
[0, 0, 2, 0]

How it works: #

• reversed(board) flips the order of the board's rows (so we start from the bottom row up).
• zip(*reversed(board)) transposes the flipped board (swaps rows with columns).
• The list comprehension converts each tuple returned by zip() into a list, giving us our rotated board.

If you prefer a manual approach (to see the coordinate transformation), you can use nested list comprehensions:

n = len(board)
rotated_clockwise = [[board[n - 1 - j][i] for j in range(n)] for i in range(n)]

This follows the rule for clockwise rotation: the value at position (i, j) in the new board comes from (n-1-j, i) in the original board (where n is the size of the square board).

2. Rotate 90 Degrees Counterclockwise #

If you ever need to rotate the other way, here's how:

# Rotate counterclockwise
rotated_counterclockwise = [list(row) for row in reversed(list(zip(*board)))]

# Or using manual list comprehension:
# rotated_counterclockwise = [[board[j][n - 1 - i] for j in range(n)] for i in range(n)]

# Print the result
for row in rotated_counterclockwise:
    print(row)

Output: #

[0, 0, 2, 0]
[0, 0, 0, 0]
[3, 0, 0, 0]
[0, 1, 0, 0]

Bonus: Fixing Your Board Generation Function #

I noticed your ctcb function was incomplete — here's a version that generates the board you provided from numlist = [1,3,0,2] (assuming the logic is: for each index i in numlist, if numlist[i] != 0, place the number i+1 at column numlist[i]-1 in row i):

def ctcb(numlist): # Create The Chess Board
    the_len = len(numlist)
    board = [[0]*the_len for _ in range(the_len)]  # Initialize empty board
    for row_idx, col_val in enumerate(numlist):
        if col_val != 0:
            # Place row_idx+1 at (row_idx, col_val-1) (since columns are 0-indexed)
            board[row_idx][col_val - 1] = row_idx + 1
    return board

# Test it out
numlist = [1,3,0,2]
generated_board = ctcb(numlist)
for row in generated_board:
    print(row)

Output: #

[0, 0, 0, 0]
[1, 0, 0, 0]
[0, 0, 0, 2]
[0, 3, 0, 0]

Perfect, that matches your original board!

内容的提问来源于stack exchange，提问作者Domenico Agosta