6.8) Nested Lists: Accessing Non-Existing Elements

If you try and refer to an element that doesn’t exist, you will get an IndexError or TypeError:

>>> L1 = [ 1, [45,57,23,32], 'twenty one', [24,52], 99 ]
>>> L1[1][3]
32
>>> L1[2][4]      # remember, strings are indexed like lists
‘t’
>>> L1[0][1]      # this element doesn’t exist
Traceback (most recent call last):
  File "<pyshell#13>", line 1, in <module>
    L1[0][1]
TypeError: 'int' object has no attribute '__getitem__'
>>> L1[3][2]      # this element doesn’t exist neither
Traceback (most recent call last):
  File "<pyshell#14>", line 1, in <module>
    L1[3][2]
IndexError: list index out of range

In the first case, L1[0] is an integer and trying to get an element of an integer (in this example, with the index [1]) doesn’t make sense. In the second case, you’re trying to get the third element in a list of length 2; the list is too short!