Chapter 4 --Page 140-141 -- Listing 4.7

The values method returns a dict_values object, not a list. However, it can be turned into a list by using the list() function. Line 10 of listing 4.7 should be

countlist = list(countlist.values())

Then the max function is legal on countlist (as shown on line 11).

The text on page 140 should read

Recall that the values() method returns a dict_values object which can be turned into a list by applying the list function.

Chapter 4 -- Page 151 -- Problem 4.46

We felt that problem 4.46 deserved a bit more detail so we added it as programming exercise 4.2. Unfortunately, we forgot to delete 4.46.  To understand more about regression lines, refer to programming exercise 4.2.

Chapter 4 -- Page 128 -- Problem 4.6d

This problem asks you to implement a function that works like the list method find. Of course, there is no method find...it should be index. The problem should read...  Implement a function that works like the list method index.

Chapter 4 -- Page 128 -- Problem 4.2g

In Python3.0, the sort method will not work across different data types. Performing sort on the list in this problem will cause an error.

>>> alist
[7, 9, 'a', 'cat', False]
>>> alist.sort()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: str() < int()