如何避免python中数组追加的引用问题[重复]

Question

我们来看看下面的代码

board = [[0,0,0],[0,0,0],[0,0,0]]
versionsOfBoard = []
versionsOfBoard.append(board); #this will keep the versions of board array
print(versionsOfBoard);
# output
# [[[0,0,0],[0,0,0],[0,0,0]]]
# later I change few values in the board and append 'board' to my versions array
board[0][0] = 1
versionsOfBoard.append(board)
print(versionsOfBoard)
# output
# [[[1, 0, 0], [0, 0, 0], [0, 0, 0]], [[1, 0, 0], [0, 0, 0], [0, 0, 0]]]
# if you notice here, the 0th index value is also changed
board[1][2] = 1
versionsOfBoard.append(board)
print(versionsOfBoard)
# output
# [[[1, 0, 0], [0, 0, 1], [0, 0, 0]], [[1, 0, 0], [0, 0, 1], [0, 0, 0]], [[1, 0, 0], [0, 0, 1], [0, 0, 0]]]

每个索引值都显示'board'的最新状态。它正在引用董事会。 我尝试过使用 .append(board[:]) 和 .append(board.copy())。这两个选项也不能解决问题。

任何帮助将不胜感激

Answer 1

试试这个

import copy
board = [[0,0,0],[0,0,0],[0,0,0]]
versionsOfBoard = []
versionsOfBoard.append(copy.deepcopy(board))
print(versionsOfBoard);

board[0][0] = 1
versionsOfBoard.append(copy.deepcopy(board))
print(versionsOfBoard)

board[1][2] = 1
versionsOfBoard.append(copy.deepcopy(board))
print(versionsOfBoard)