Sudoku Sequence Generator

sudoku_generator.py

import numpy as np

# Generator for all possible sudoku grids
def sudoku_generator(sudoku):
    for y in range(9):
        for x in range(9):
            # If cell not filled
            if sudoku[y][x] == 0:
                # Check if any number in the range is valid in the empty cell
                for n in range(1,10):
                    if is_valid(n, y, x, sudoku):
                        sudoku[y][x] = n
                        yield from sudoku_generator(sudoku)
                        # Reset the cell for backtracking
                        sudoku[y][x] = 0
                return
    yield sudoku

def is_valid(n, y, x, sudoku):
    # Check if number valid in row
    for i in range(9):
        if sudoku[y][i] == n:
            return False
    # Check if number valid in column
    for j in range(9):
        if sudoku[j][x] == n:
            return False
    # Check if number valid in respective 3x3 tile
    for i in range(3):
        for j in range(3):
            if sudoku[y//3*3+i][x//3*3+j] == n:
                return False
    return True

if __name__ == '__main__':
    # empty sudoku grid
    sudoku = np.zeros((9,9), dtype=np.int)

    sudoku_seq_generator = sudoku_generator(sudoku)
    range_limit = 10
    for i in range(range_limit):
        print(next(sudoku_seq_generator))