Lecture Notes on 17 Apr 2017

def is_magic (b):
  # sum the first row
  canon_sum = 0
  for j in range (len(b[0]):
    canon_sum += b[0][j]

  # sum each row and compare with canon_sum
  for i in range (len(b)):
    sum_n = 0
    for j in range (len(b[i])):
      sum_n += b[i][j]
    if (sum_n != canon_sum):
      return False

  # sum each column and compare with canon_sum
  for j in range (len(b[0])):
    sum_n = 0
    for i in range (len (b)):
      sum_n += b[i][j]
    if (sum_n != canon_sum):
      return False

  # sum the diagonal elements going left to right
  sum_lr = 0
  for i in range (len(b)):
    sum_lr += b[i][i]
  if (sum_lr != canon_sum):
    return False

  # sum the diagonal elements going right to left
  sum_rl = 0
  for i in range (len(b)):
    sum_rl += b[i][len(b) - 1 - i]
  if (sum_rl != canon_sum):
    return False

  return True


def main():

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

  print (is_magic (b))

main()

# go through a 2D list in groups of four elements

def main():
  # open the file
  in_file = open ("./grid.txt", "r")

  # read the dimension of the grid
  dim = in_file.readline()
  dim = dim.strip()
  dim = int(dim)

  # create an empty grid
  grid = []

  # populate that grid
  for i in range (dim):
    line = in_file.readline()
    line = line.strip()
    row = line.split()
    for j in range (dim):
      row[j] = int (row[j])
    grid.append (row)

  # print the grid
  # print (grid)

  # read each row in blocks of four
  for row in grid:
    for i in range (dim - 3):
      prod = 1
      for j in range (i, i + 4):
        prod = prod * row[j]
      print(prod, end = " ")
  print()

  # read each column in blocks of four
  for j in range (dim):
    for i in range (dim - 3):
      for k in range (i, i + 4):
        print (grid[k][j], end = " ")
      print (end = "    ")
    print ()

  # go along all diagonals L to R in blocks of 4
  for i in range (dim - 3):
    for j in range (dim - 3):
      for k in range (4):
        print (grid[i + k][j + k], end = " ")
      print (end = "    ")
    print ()


main()