Problem with List Reference

[CH_NoLuck]

Hello,

I am currently working on a school project where we should solve an 8-Puzzle (3x3 grid with 8 tiles. You can always move one tile to the empty spot). I created 2-dimensional list with numbers 1-8 + 0. 0 Marks the empty spot.

Now I am using the following code to move one tile (I want to move the 6 to 0 (and vice versa).

I know that I need to create a copy() of the list, so it is not referenced. But I still get the output wrong. It changes both lists.

I tried to find a solution to the problem, but all suggestions are to make a copy, what I am doing right now.

Thank you for any help!

Best regards,
NoLuck

My Code:

exampleState = [[1, 2, 3], [4, 5, 6], [7, 8, 0]]

movedState = exampleState.copy()



newList = exampleState.copy()

for i in range(len(newList)):
    for j in range(len(newList[i])):
        if newList[i][j] == 0:
            iPos = i
            jPos = j
    
numMove = int(movedState[iPos-1][jPos])
movedState[iPos][jPos] = int(numMove)
movedState[iPos-1][jPos] = 0
    
print("moved state:", movedState)
print("input state:", exampleState)

My Output:

Output:
moved state: [[1, 2, 3], [4, 5, 0], [7, 8, 6]]
input state: [[1, 2, 3], [4, 5, 0], [7, 8, 6]]

[CH_NoLuck]

I figured that i should use

movedState = copy.deepcopy(exampleState)