CODEWITHSUNDEEP
pythonlistboolean
Akito L
Akito L

Reputation: 13

How to reverse a given Boolean value in a list?

I'm trying to solve the Lights Out puzzle. I use a two-dimensional list of Boolean values, such as [[True, True, True], [True, True, True], [True, True, True]], to represent the condition of a light. I want to reverse the boolean value at a given location such as (1,1), and I code as:

class LightsOutPuzzle(object):

    def __init__(self, board):
        self.board = board

    def get_board(self):
        return self.board

    def perform_move(self, row, col):      
        self.board[row][col] = not self.board[row][col]
        print(self.board)
        return LightsOutPuzzle(self.board)

I call perform_move(1,1) on

[[False, False, False], [False, False, False], [False, False, False]]

but the result is:

[[False, True, False], [False, True, False], [False, True, False]]

which makes me confused. Could you please tell me what's wrong with it? What is the right way to do this task? Thanks a lot for helping!

I'm using this function to generate new boards:

def create_puzzle(rows, cols):
    c = []
    r = []
    for x in range(cols):
        c.append(False)
    for y in range(rows):
        r.append(c)
    return LightsOutPuzzle(r)

Does it cause the problem?

Thank you sooooo much for your replies!!! QWQ

Upvotes: 1

Views: 201

Answers (2)

Shivam Seth
Shivam Seth

Reputation: 687

The probe statement i saw in your code is in function def create_puzzle(rows, cols)

def create_puzzle(rows, cols):

c = []
r = []

for x in range(cols):  
    c.append(False)    #Statement1

for y in range(rows):  
    r.append(c)        #Statement2

return LightsOutPuzzle(r)

Statement1 : Appends elements to list #[False, False, False] Suppose id(c) is 0x1000

Statement2 : This statement will append Same List (c) to your rowList result (reference id) : [0x1000, 0x1000, 0x1000]

So your row will have reference to same List, This is the reason when you make change in one of the columns List it is reflecting in all other columns Lists as well

Change your create_puzzle

def create_puzzle(rows, cols):

     myBoard = [[False]*cols for i in range(rows)]
     return LightsOutPuzzle(myBoard )

Upvotes: 1

Belal Abdulnasser
Belal Abdulnasser

Reputation: 36

you can do it inside the init method itself then change the perform_move method, try this

class LightsOutPuzzle(object):

def __init__(self, board):
    self.board = board
    board = [not i for i in board]
    print(board)

def get_board(self):
    return self.board

def perform_move(self, row, col):
    self.board[row][col] = not self.board[row][col]
    print(self.board)
    return LightsOutPuzzle(self.board)

def main():
    LightsOutPuzzle([False, False, False])


if __name__ == '__main__':
    main()

Upvotes: 0

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