Lecture Notes on 14 Apr 2017

Read Chapter 11: Multidimensional Lists

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


def main():
  b = [[4, 9, 2], [3, 5, 7], [8, 1, 6]]

  print (b[2][1])

  # sum all elements
  sum_n = 0
  for row in b:
    for col in row:
      sum_n += col
  print (sum_n)

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

  # find the max in the 2D 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)

  # make a deep copy of a 2D 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)

  # 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)

main()