Chapter 8 – The Transposition Cipher, Encrypting 111'dog'
spam[0][1]
'cat'
spam[1][0]
1
spam[1][1]
2
The double index brackets used for spam[0][0] work because spam[0] evaluates to
['dog', 'cat'] and ['dog', 'cat'][0] evaluates to 'dog'. You could even use
another set of index brackets, since string values also use them:
spam = [['dog', 'cat'], [1, 2, 3]]
spam[0][1][1]
'a'
Say we had a list of lists stored in a variable named x. Here are the indexes for each of the items
in x. Notice that x[0], x[1], x[2], and x[3] refer to list values:
Figure 8-1. A list of lists with every item’s index labeled.Practice Exercises, Chapter 8, Set C
Practice exercises can be found at http://invpy.com/hackingpractice 8 C.
Using len() and the in Operator with Lists
We’ve used the len() function to tell us how many characters are in a string (that is, the length
of the string). The len() function also works on list values and returns an integer of how many
items are in the list.