Magic Square

grid = [[54,12 , 0, 0],
        [0, 39, 0, 30],
        [33,27,24, 42],
        [18, 0, 0, 0 ]]
w = len(grid) #height or width

#instructions to dynamically generate rows, columns, diagonals coords
dirs = {i:[(w,1)[not i%w]] for i in range(w*w) if i<w or i%w==0} #rows, columns
dirs[0].extend([w, w+1])
dirs[w-1].append(w-1)

def get_spot_coords(start, step): #generate row, column or diagonal coords
    end = w * step + start
    return [divmod(i,w) for i in range(start, end, step)]

target = 0 #target sum
for start in dirs.keys():
    for step in dirs[start]:
        temp = [grid[x][y] for x,y in get_spot_coords(start, step)]
        if temp.count(0)==0: target = sum(temp)

while not all(grid[i//w][i%w] > 0 for i in range(w*w)):
    for start in dirs.keys():
        for step in dirs[start]:
            spot = get_spot_coords(start, step)
            if sum(grid[x][y]>0 for x, y in spot) == w-1:
                x, y = [(x,y) for x,y in spot if grid[x][y]==0][0]
                grid[x][y] = target - sum(grid[i][j] for i,j in spot)
print(*grid, sep='\n')