"Python 2.4 introduces two built-in set types, set and frozenset, to represent arbitrarily ordered collections..."

Actually, they're unordered as is stated in the last sentence of the following paragraph: "Sets and frozensets are not ordered."

I expect this is actually just a typo but I've flagged it as a technical mistake as the resulting text makes sense, is not right and could mislead.

The mathematical nature of this excellent book brings out the nitpickiest
elements of the mathematician in me.

The sentence "For example, x=x+y does not modify the object to which name x was
originally bound" is incorrect, I think. Suppose x and y belong to a user-defined
class in which __add__ has been defined. Suppose __add__(self, other) changes some
attribute (say 'value') of self. Suppose we make the statements:

z=x
x = x+y
print z.value

The point of the discussion in the book is that x is reassigned, not changed in
place. However, the object originally bound to x will be changed in place, and that
change can be seen here in z.

The introduction of a custom __add__ is not so out of left field here, since
the book is contrasting the situation to when the object has a custom __iadd__.

The book says:
x[1:4]=[8,9] # x is now [1,8,9,4]

But it should say:
x[1:4]=[8,9] # x is now [1,8,9]

Here, the book says:"When __init__ is absent, you must call the class without arguments, and the newly
generated instance has no instance-specific attributes." I find this incorrect.

For example, consider the code snippet below:
>>> class A(object):
def __init__(self,x):
self.x=x

>>> class B(A):
pass

>>> b1=B()
Traceback (most recent call last):
File "<pyshell#19>", line 1, in <module>
b=B()
TypeError: __init__() takes exactly 2 arguments (1 given)

>>> b2=B(23)
>>> b2
<__main__.B object at 0x012927B0>
>>> b2.x
23

The mistake corresponds to the issue of "class inheritance".

For this code block to be illustrative of the distinction between legacy- and new-style resolution order and to be consonant with the phrase '...for the case of this kind of "diamond-shaped" inheritance graph' in the second paragraph on the following page class Base3, like Base2, should derive from Base1.

With Base3 not deriving from Base1 the code prints "Base1" even if it is modified to be new-style (by deriving Base1 from object).

In the __getitem__ example, self.indices should be index.indices; also, one
parenthesis seems to be missing at the end.

The text accurately describes a slice object has having
a method called 'indices'. In the code example, however,
the invoking object is not a slice. E.g.,

The author intended:

return self.__class__(self[x]
for x in xrange(*index.indices(len(self))))

instead of:

return self.__class__(self[x]
for x in xrange(*self.indices(len(self)))

# the latter is also missing the final closing
# parenthesis

The integer code returned for unicode is [0,65534], but shouldn't it be 65535? But
if it cannot return 65535, I would have appreciated knowing why it wouldn't.

result of reduce() is the product of a sequence of numbers, but it is getting bound
to 'thesum'.

>>> import collections, operator
>>> def sorted_histograms(seq):
d = collections.defaultdict(int)
for item in seq: d[item] += 1
print d
return sorted(d.iteritems, key=operator.itemgetter(1), reverse=True)

>>> a = [ "b", "c", "d", "b", "c", "c", "e", "d"]
>>> b = sorted_histograms(a)
defaultdict(<type 'int'>, {'c': 3, 'b': 2, 'e': 1, 'd': 2})

Traceback (most recent call last):
File "<pyshell#4>", line 1, in <module>
b = sorted_histograms(a)
File "<pyshell#2>", line 9, in sorted_histograms
return sorted(d.iteritems, key=operator.itemgetter(1), reverse=True)
TypeError: 'builtin_function_or_method' object is not iterable
>>> b

Traceback (most recent call last):
File "<pyshell#5>", line 1, in <module>
b
NameError: name 'b' is not defined

Doesn't heappop run in O(log(len(alist))) time instead of O(len(alist))? If it was
O(len(alist)), then heapsort would be O(n^2).

Change:
the built-in function repr (covered in repr on page 198)
to:
the built-in function __repr__ (covered in __repr__ in page 108)

Quote: "In other words, there is no way in which the caller of popen2, popen3, or popen4 can learn about P's termination code."

"no way" is a bit harsh here. You can get it with python tools if you set a signal handler for SIGCHLD and reap the childinfo with wait* calls.

fmt parameter is missing in function prototype.

fmt argument missing from prototype.

The second timedelta() call in the "print repr(timedelta...)" examples should be
changed from
timedelta(minutes=0.5)
to
timedelta(hours=-1)

for the example output to be correct.

Quote: "In other words, there is no way in which the caller of popen2, popen3, or popen4 can learn about P's termination code."

"no way" is a bit harsh here. You can get it with python tools if you set a signal handler for SIGCHLD and reap the childinfo with wait* calls.

it uses both "Import Tkinter" and "from Tkinter import *".
The first is unnecessary and would be incorrect if the other was removed.

the second instance of 'justoneword' should be reversed:

self.assertEqual(mod.reverseWords('justoneword'), 'justoneword')
should be:
self.assertEqual(mod.reverseWords('justoneword'), 'drowenotsuj')

The example in this section was how to quickly sort a list of strings based on the second word in each
string. The operator.itemgetter technique incorrectly sorts based on the second character in each string,
not the second word.

Maybe use something like:

L.sort(key=lambda x: x.split()[1])

It talks about POP protocol, and should talk about NNTP protocol.

Example program produces error message:

"Traceback (most recent call last):
File "C:xmlrpctest.py", line 6, in <module>
results = proxy.meerkat.getItems({'search':'Python', 'num_items':7})
File "C:Python25Libxmlrpclib.py", line 1147, in __call__
return self.__send(self.__name, args)
File "C:Python25Libxmlrpclib.py", line 1437, in __request
verbose=self.__verbose
File "C:Python25Libxmlrpclib.py", line 1191, in request
headers
ProtocolError: <ProtocolError for www.oreillynet.com/meerkat/xml-rpc/server.php: 301 Moved Permanently>"