Traversing sub squares in sudoku

Question

I have a 2d array of n^2Xn^2 dimensions (like a sudoku board, does not have to be valid numbers). I want to traverse each subsquare of nXn elements and put them into an array, but I'm having difficulty structuring the for loops.

If n=2, then my sudoku board could look like this:

[[1,2,3,4],
 [5,6,7,8],
 [9,10,11,12],
 [13,14,15,16]]

And I want to traverse 1,2,5,6 then 3,4,7,8 then 9,10,13,14 then 11,12,15,16. I'm guessing there should be four for loops, two of them nested, but I'm having difficulty structuring them. I was thinking the first one should be something like

for i in range(0,n^2,int(n^2/n)): 
   something nested here
Someting here
   something nested here

Answer 1

The terminology for this set of cells in sudoku is usually a region. Organizing it as four for loops is fairly natural, the outer two controlling which region you are looking at and the inner two scanning the cells within the region.

n = 3    # gives a 9x9 grid
for reg_r in range(n):
    for reg_c in range(n):
        for r in range(n):
            for c in range(n):
                print(board[n*reg_r + r][n*reg_c + c])
        print('--------')