无法创建实例变量(Python)的副本
我用python创建了一个数独类,我想解决板的问题,并在原始板上保留一个实例变量,但是当我使用使用递归回溯算法无法创建实例变量(Python)的副本,python,backtracking,Python,Backtracking,我用python创建了一个数独类,我想解决板的问题,并在原始板上保留一个实例变量,但是当我使用使用递归回溯算法self.board的solve()方法时,会随着self.solved\u board一起改变,这是为什么呢,我怎样才能在原始副本中保留一个变量 grid = [ [3, 0, 6, 5, 0, 8, 4, 0, 0], [5, 2, 0, 0, 0, 0, 0, 0, 0], [0, 8, 7, 0, 0, 0, 0, 3, 1], [0, 0,
self.board
的solve()
方法时,会随着self.solved\u board
一起改变,这是为什么呢,我怎样才能在原始副本中保留一个变量
grid = [ [3, 0, 6, 5, 0, 8, 4, 0, 0],
[5, 2, 0, 0, 0, 0, 0, 0, 0],
[0, 8, 7, 0, 0, 0, 0, 3, 1],
[0, 0, 3, 0, 1, 0, 0, 8, 0],
[9, 0, 0, 8, 6, 3, 0, 0, 5],
[0, 5, 0, 0, 9, 0, 6, 0, 0],
[1, 3, 0, 0, 0, 0, 2, 5, 0],
[0, 0, 0, 0, 0, 0, 0, 7, 4],
[0, 0, 5, 2, 0, 6, 3, 0, 0] ]
class Sudoku:
def __init__(self, board):
self.board = board
self.solved_board = board[:] #<--- I used the [:] because I thought this will create a new list
def get_board(self):
return self.board
def set_board(self, board):
self.board = board
self.solved_board = board
def print_original_board(self):
self.print(self.board)
def print_solved_board(self):
self.print(self.solved_board)
def print(self, board):
"""Receiving a matrix and printing a board with seperation"""
for i in range(len(board)):
if i % 3 == 0 and i!=0:
print('---------------------------------')
for j in range(len(board[i])):
if j%3==0 and j!=0:
print(" | ", end='')
print(" " + str(board[i][j]) + " ", end='')
print('')
def find_empty(self,board):
"""Receiving a matrix, loops through it, and return a tuple
with the row and the column of the free stop in the matrix"""
for i in range(len(board)):
for j in range(len(board[i])):
if board[i][j]==0:
return (i,j)
return None
def is_valid(self, board, num, pos):
"""Receiving matrix, a number we want to insert, and a tuple with the row and col
and will check if the row, col, and box are valid so we can place the number
in the position"""
# Check row
for i in range(len(board[pos[0]])):
if pos[0] != i and board[pos[0]][i] == num:
return False
# Check col
for i in range(len(board)):
if pos[1] != i and board[i][pos[1]] == num:
return False
pos_row = pos[0] // 3
pos_col = pos[1] // 3
for i in range(pos_row*3 ,pos_row*3 + 3):
for j in range(pos_col * 3, pos_col*3 + 3):
if (i,j) != pos and board[i][j] == num:
return False
return True
def solve(self):
"""Using backtracking algorithm to solve the solved_board variable"""
find = self.find_empty(self.solved_board)
if not find:
return True
else:
row, col = find
for i in range(1,10):
if(self.is_valid(self.solved_board, i, (row, col))):
self.solved_board[row][col] = i
if self.solve():
return self.solved_board
self.solved_board[row][col] = 0
return False
sudoku = Sudoku(grid)
sudoku.print_original_board()
print(" ")
sudoku.solve()
sudoku.print_original_board() # <---- This prints the solved board
grid=[[3,0,6,5,0,8,4,0,0],
[5, 2, 0, 0, 0, 0, 0, 0, 0],
[0, 8, 7, 0, 0, 0, 0, 3, 1],
[0, 0, 3, 0, 1, 0, 0, 8, 0],
[9, 0, 0, 8, 6, 3, 0, 0, 5],
[0, 5, 0, 0, 9, 0, 6, 0, 0],
[1, 3, 0, 0, 0, 0, 2, 5, 0],
[0, 0, 0, 0, 0, 0, 0, 7, 4],
[0, 0, 5, 2, 0, 6, 3, 0, 0] ]
类数独游戏:
def ___;初始(自我,板):
self.board=board
self.solved_board=board[:]#是的,board[:]
确实创建了一个新的列表——所有这些旧的内部列表:
[23]中的board=[1]、[2]]
在[24]中:board2=板[:]
在[25]中:board2[0]是board[0]
Out[25]:对
[26]中:board2[0][0]+=10
在[28]中:板
出[28]:[11],[2]]
你需要复制它;e、 g
solved_board=[row[:]代表board中的行]
self.solved_board=board[:]
确实创建了一个新列表,但它引用了与board
相同的内部列表。你需要更深一层:
self.solved_board = [row[:] for row in board]
尝试deepcopy方法
from copy import deepcopy
def __init__(self, board):
self.board = board
self.solved_board = deepcopy(board)
你需要做一份深度拷贝,那是一个列表列表。