Lecture Notes on 27 Oct 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 comapre 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 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 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 ():
  # create a 2-D list
  b = [[4, 9, 2], [3, 5, 7], [8, 1, 6]]

  # sum the elements in a 2-D list
  sum_n = 0
  for row in b:
    for col in row:
      sum_n += col
  print (sum_n)
  print ()

  sum_n = 0
  for i in range (len(b)):
    for j in range (len(b[i])):
      sum_n += b[i][j]
  print (sum_n)
  print ()

  # get the maximum in a 2-D list
  max_n = b[0][0]
  for i in range (len(b)):
    for j in range (len(b[i])):
      if (b[i][j] > max_n):
        max_n = b[i][j]
  print (max_n)
  print

  # make an exact copy of the 2-D list
  c = []
  for i in range (len(b)):
    d = []
    for j in range (len(b[i])):
      d.append (b[i][j])
    c.append (d)

  # transpose a 2D list
  c = []
  for j in range (len(b[0])):
    d = []
    for i in range (len(b)):
      d.append (b[i][j])
    c.append (d)
  print (c)
  print ()

  # add two 2-D lists
  d = []
  for i in range (len(b)):
    e = []
    for j in range (len (b[i])):
      f = b[i][j] + c[i][j]
      e.append (f)
    d.append (e)
  print (d)
  print()

main()