A list can contain other lists. By using this nifty feature you can store more complicated data. Consider the following example –

test_scores = []
test_scores.append(["bert", [76, 21, 43]])
test_scores.append(["sue", [11,9,92,12]])
for student in test_scores:
      print "Student - ", student[0]
      total_score = 0
      for score in student[1]:
           total_score = total_score + score
      average = total_score / len(student[1])
      print "average score", average

The above code is a little more complex than other examples used in this tutorial. There are two main entries in the first list

test_scores.append([“bert”, [76, 21, 43]]) and
test_scores.append([“sue”, [11,9,92,12]])

At position 0 is a name and at position 1 is another list containing all of that students test scores. In order to enable the list with a list you must be mindful of the square brackets. They must balance up!

The outer for in loop goes over each student and the inner for in loop goes over the test scores. Notice the inner loop uses student[1].If you remember that position 1 contains the test score list and hopefully this will make sense.

Write a short program which will add up the following numbers. You will need to use two for in loops!

nums = [[4,3,1], [3,2], [4,8,9]]