Lists are a very useful construction and one of the basic types in Python. A Python list is an ordered list of objects enclosed by square brackets. You can access the elements of a list using zero-based indexes inside square brackets:

L1 = [5, 6]
L1[0] # 5
L1[1] # 6
L1[2] # raises IndexError
L2 = ['a', 1, [3, 4]]
L2[0] # 'a'
L2[2][0] # 3
L2[-1] # last element: [3,4]
L2[-2] # second to last: 1

The indexing of the elements starts at zero. You can put objects of any type inside a list, even other lists. Some basic list functions are as follows:

• list(range(n))} creates a list with n elements, starting with zero:

      print(list(range(5))) # returns [0, 1, 2, 3, 4]

• len gives the length of a list:

      len(['a', 1, 2, 34]) # returns 4
      len(['a',[1,2]]) # returns 2

• append is used to append an element to a list:

      L = ['a', 'b', 'c']
      L[-1] # &apos...