Program which takes a Sodoku puzzle as input and solves it for you. The puzzle has to given as a string combining the row wise and filling the empty values with 0.

sudoku.py

puzzle = "004006079000000602056092300078061030509000406020540890007410920105000000840600100"

def line_to_grid(values):
    grid = []
    for i in range(0,9):
        grid.append(list(map(lambda x: int(x), list(values[i*9:(i+1)*9]))))
    return grid

def grid_to_line(grid):
    line = ""
    line = [line + str(i) for row in grid for i in row]
    return "".join(line)

def small_grid(c, r):
    for i in range(int(c/3) * 3, (int(c/3) * 3) + 3):
        for j in range(int(r/3) * 3, (int(r/3) * 3) + 3):
            if not (i == c and j == r):
                yield (i,j)

def detect_possible(grid, c, r):
    possible = [1,2,3,4,5,6,7,8,9]
    # Ignoring if the values is already filled
    if grid[r][c] is not 0:
        return False
    # Removing small grid number from possible combinations
    for v, k in small_grid(c, r):
        if grid[k][v] in possible:
            possible.remove(grid[k][v])
    # Removing same row filled values 
    [possible.remove(rv) for rv in grid[r] if rv in possible]
    # Removing same column filled values 
    [possible.remove(grid[i][c]) for i in range(0,len(grid)) if grid[i][c] in possible]
    return possible


## change the following to recursive method
grid = line_to_grid(puzzle)
grid_poss = {}
while True:
    count = 0
    for i in range(0,9):
        for j in range(0,9):
            grid_poss[(i,j)] = detect_possible(grid, r=i, c=j)
            if not grid_poss[(i,j)]:
                count += 1
            elif len(grid_poss[(i,j)]) == 1:
                grid[i][j] = grid_poss[(i,j)][0]
    if count == 81:
        break

grid_to_line(grid)