Displaying sudoku program in python

I have to update a nested list sudoku with grids and borders. My output is not printing as intended and I am not sure how to fix it. This is my code with the test input cases and intended output vs output right now.

The code below has the following:

  1. There are three nested sudoku lists that I need to update with grid lines and borders.
  2. Next is my code and the intended output for the three sudoku boards.
  3. Lastly, the link has my output right now

This is the description:

Prints a given board to the console in a way that aligns the content of columns and makes the subgrids visible.
Input : a Sudoku board (board) of size 4×4, 9×9, or 16×16
Effect: prints the board to the console

small = [[0, 0, 1, 0],
         [4, 0, 0, 0],
         [0, 0, 0, 2],
         [0, 3, 0, 0]]

big = [[0, 0, 0, 0, 0, 0, 0, 0, 0],
       [4, 0, 0, 7, 8, 9, 0, 0, 0],
       [7, 8, 0, 0, 0, 0, 0, 5, 6],
       [0, 2, 0, 3, 6, 0, 8, 0, 0],
       [0, 0, 5, 0, 0, 7, 0, 1, 0],
       [8, 0, 0, 2, 0, 0, 0, 0, 5],
       [0, 0, 1, 6, 4, 0, 9, 7, 0],
       [0, 0, 0, 9, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 3, 0, 0, 0, 2]]

giant = [[0, 5, 0, 0, 0, 4, 0, 8, 0, 6, 0, 0, 0, 0, 9, 16],
         [1, 0, 0, 0, 0, 0, 0, 13, 4, 0, 0, 7, 15, 0, 8, 0],
         [13, 0, 0, 0, 0, 7, 3, 0, 0, 0, 0, 9, 5, 10, 0, 0],
         [0, 11, 12, 15, 10, 0, 0, 0, 0, 0, 5, 0, 3, 4, 0, 13],
         [15, 0, 1, 3, 0, 0, 7, 2, 0, 0, 0, 0, 0, 5, 0, 0],
         [0, 0, 0, 12, 0, 3, 0, 5, 0, 11, 0, 14, 0, 0, 0, 9],
         [4, 7, 0, 0, 0, 0, 0, 0, 12, 0, 15, 16, 0, 0, 0, 0],
         [0, 0, 0, 0, 14, 0, 15, 0, 6, 9, 0, 0, 0, 0, 12, 0],
         [3, 0, 15, 4, 0, 13, 14, 0, 0, 0, 0, 1, 0, 0, 7, 8],
         [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 10, 0, 0, 0, 0],
         [11, 0, 16, 10, 0, 0, 0, 0, 0, 7, 0, 0, 0, 3, 5, 0],
         [0, 0, 13, 0, 0, 0, 0, 0, 14, 0, 15, 16, 0, 9, 0, 1],
         [9, 0, 2, 0, 0, 14, 0, 4, 8, 0, 0, 0, 0, 0, 0, 0],
         [0, 14, 0, 0, 0, 0, 0, 10, 9, 0, 3, 0, 0, 0, 1, 7],
         [8, 0, 0, 0, 16, 0, 0, 1, 2, 14, 11, 4, 0, 0, 0, 3],
         [0, 0, 0, 1, 0, 0, 5, 0, 0, 16, 0, 6, 0, 12, 0, 0]]

import math

def print_board(board):
    board_size = len(board)
    l = int(board_size + math.sqrt(board_size) + 1)
    section = int(math.sqrt(board_size))
    border = 0
    i_index = 0

    for i in range(0, l):
        if (i == border):
            print('-' * l)
            border = border + section + 1
        else:
            inner_border = 0
            j_index = 0
            for j in range(0, l):
                if (j == inner_border):
                    print('|', end='')
                    inner_border = inner_border + section + 1
                else:
                    if (board[i_index][j_index] == 0):
                        print(' ', end='')
                    else:
                        if (board[i_index][j_index] < 10):
                            print(board[i_index][j_index], end='')
                        if (board[i_index][j_index] == 10):
                            print('A', end='')
                        if (board[i_index][j_index] == 11):
                            print('B', end='')
                        if (board[i_index][j_index] == 12):
                            print('C', end='')
                        if (board[i_index][j_index] == 13):
                            print('D', end='')
                        if (board[i_index][j_index] == 14):
                            print('E', end='')
                        if (board[i_index][j_index] == 15):
                            print('F', end='')
                        if (board[i_index][j_index] == 16):
                            print('G', end='')
                    j_index = j_index + 1
            i_index = i_index + 1


print(print_board(small))

print(print_board(big))

print(print_board(giant))

Intended output:

    -------
    |  |1 |
    |4 |  |
    -------
    |  | 2|
    | 3|  |
    -------
    >>> print_board(big)
    -------------
    |   |   |   |
    |4  |789|   |
    |78 |   | 56|
    -------------
    | 2 |36 |8  |
    |  5|  7| 1 |
    |8  |2  |  5|
    -------------
    |  1|64 |97 |
    |   |9  |   |
    |   | 3 |  2|
    -------------
    >>> print_board(giant2)
    ---------------------
    | 5  | 4 8| 6  |  9G|
    |1   |   D|4  7|F 8 |
    |D   | 73 |   9|5A  |
    | BCF|A   |  5 |34 D|
    ---------------------
    |F 13|  72|    | 5  |
    |   C| 3 5| B E|   9|
    |47  |    |C FG|    |
    |    |E F |69  |  C |
    ---------------------
    |3 F4| DE |   1|  78|
    |    |    |  9A|    |
    |B GA|    | 7  | 35 |
    |  D |    |E GF| 9 1|
    ---------------------
    |9 2 | E 4|8   |    |
    | E  |   A|9 3 |  17|
    |8   |G  1|2EB4|   3|
    |   1|  5 | G 6| C  |
    ---------------------

My output:

My_output

Answer

You need to print a newline character between each row, easiest way to do it is to use print() when you want to create a new line.

try this:

# ...
i_index = i_index + 1
print()
# ...

When you increase the i_index parameter you are basically going over to the next line, so this is where you want your print() statement as well

Also, since you are using print inside the function print_board(), you don’t need to use print(print_board(big)) for example, you should just use print_board(big). that is why you are seeing None printed between each board (because print_board() returns None)