[Core Python Programming]

Errata/Corrigenda

Apr 2009 NOTE: most of the errata items listed below are being proactively corrected in current and future printings of this book, so it is highly possible that they don't exist in your version, especially if you purchased your book in 2009 and moving forward. We will begin a new errata list for all newer printings, however we leave the old ones here for completeness in case someone picks up an older printing.

There will inevitably be errors when writing a book no matter how hard we try to keep it clean. In other words, "Don't (necessarily) believe everything you read!" A lot of hands touch the text before the book finally ends up in your hands, so here is where we try to clean it up. Even some of my own corrections found in the draft were not implemented due to lack of time or priority during the highly-compressed editing phase.

With regards to the corrections to the source code for the Examples in the book, MINOR problems do not prevent the script from running, but CRITICAL bugs means that the code printed as-is will not execute. We will provide changes or differences ("diffs") whenever possible. The diffs between the files are -u context diffs for those of you who know what they are. Because there is no other source for getting the code, all of the scripts for download have already been corrected.

Download PDF Versions

If you find a new problem, send it to us at corepython (at) yahoo.com. Each errata item follows the format below... submit yours using the same format so that we can upload it faster to this page. We are also interested in hearing comments, suggestions, and general feedback, both good and bad. We want to continue improving the book for future readers and editions! MANY THANKS!!

Page(s) :: Section (may also have Figure, Table, or Example number) :: Subsection (if appl.) : correction

• Text which is in red indicates a change.
• Text which is in gray indicates an erratum that is of lower priority that is not normally displayed. Use the Toggle button below to swap between showing and hiding all minor errata.
• Errata denoted by NEW or UPDATED were added/changed between Feb 2008 and May 2008.

FrontMatter

xxx :: Preface : Chapter Guide : Chapter 8 : In the first sentence, for, while, and if should be in Courier Bold font, as all keywords are.

xxxiv :: Preface : Book Resources : In the second sentence, add a comma between "errata" and "source code".

Chapter 1

1-2 :: 1 : The book is misnumbered... page "1" is missing. The final page of the Preface is xxxvii and jumps immediately to page 2 of the main body of text.

11 :: 1.4 :: Build It Yourself : The third step, make install will install the Python you just compiled and set it as the default Python interpreter. Should you wish to install multiple versions of the interpreter or do not wish to replace the existing version, use make altinstall. For example, if you have an existing Python 2.4.3 installtion then build and install 2.5 with make altinstall, calling python from the command-line still launches the 2.4.3 interpreter whereas to start 2.5, you would need to use python2.5.

17 :: 1.5.2 :: Unix : In the final paragraph of this section, we should also point out that executing $ script.py directly from the command-line only works if the current directory is part of your PATH environment variable. If it is not, you have to use ./ in front of the script name so that it can be found, e.g., $ ./script.py.

21 :: 1.5.4 :: Open Source : We inadvertently left out another popular IDE called Stani's Python Editor (SPE). The link to it: http://pythonide.stani.be/

NEW
24 :: 1.7 : The last sentence of the second paragraph needs to insert "of its", as in: "... Python has several of its own Web...". In the first sentence of the next paragraph, the word "shares" appears twice. Replace the second one with "with", as in: "... shares similarities with Python."

Chapter 2

33 :: 2.1 :: Core Note : In the final part of this sidebar, when dumping the previous expression using the underscore, the output should be in quotes: 'Hello World!' (since the string itself is the expression and not its contents).

33 :: 2.1 : In the middle paragraph, delete the superfluous sentence that begins with, "Python is fairly flexible...."

34 :: 2.5 : Just about the Core Note, we should warn the reader by adding the following as the final sentence of that paragraph: "Readers should be cautioned that users need to enter a valid Python integer when prompted for a number as anything other than such will cause int() to raise an error because it cannot convert the input into a valid Python integer."

37 :: 2.5 : In the second sentence of the final paragraph at the bottom of the page, change the -- to the unary negation sign - (single hyphen instead of two).

38-39 :: 2.6 : In the section preceding the call to decimal.Decimal(), we mention that "[you] must import the decimal module to use these types of numbers," but we didn't do so at the top of p. 39, so add the following at the top: >>> import decimal.

41 :: 2.10 : In the 2nd (and final) paragraph, change "***" to "device".

NEW
41 :: 2.11 : In the first sentence of the final paragraph, replace "then the statement" with "the". Also replace the word "otherwise" with "then".

42 :: 2.11 : In the first print statement at the top of the page, there should be a space to separate "at" and "least".

43 :: 2.12 : The sequence in the first for loop should not wrap.

47 :: 2.15 : How to Open a File : Replace the code snippet near the top of the page with: 
filename = raw_input('Enter file name: ')
fobj = open(filename, 'r')
data = fobj.readlines()
fobj.close()
for eachLine in data:
    print eachLine,

52 :: 2.18 :: How to Create Class Instances : In the (first [John Doe]) sample output for calling foo1.showname(), the output should not have "__main__." in it. In other words, it should just be:

>>> foo1.showname()
Your name is John Doe
My name is FooClass

Chapter 3

NEW
63 :: 3.1.4 :
  • In the first sentence of the paragraph immediately beneath the Core Style sidebar, the word "and" has an extra space in it that should be removed.
  • In the first sentence of the next paragraph, replace the last part of the sentence so that it reads as, "...more elegant and contributes to the goal of making the code easier to read.

    68 :: 3.3.2 :: Table 3.1 : The keywords as and assert should be in Courier Bold, like they are in the equivalent table in Appendix A on p. 1022.

    69 :: 3.3.3 : Add the following as the final sentence of this subsection: "Also see the Core Tip on p. 258 in Chapter 7."

    • 80 :: 3.6 :: Example 3.1 : makeTextFile.py
  • The code for line 10 is missing. It should be fname = raw_input('Enter file name: ') and indented at the same level line 11 below it.
  • The text markers for lines 12 and 31, i.e, the "12" and "31" themselves, should not be in Courier/mono. Line 12 should be indented at the same level as line 14.
  • Change line 6 to be a blank line (removing the os.linesep() reference). (Yes, both lines 6 and 7 are blank now.)
  • Replace line 30 with fobj.write('\n'.join(all))

    * Description of the 3rd and 4th changes for those who are curious: our goal for keeping the text file platform-independent was defeated by the fopen() C library call on Win32 platforms. For each NEWLINE (\n) character encountered, it is replaced by CARRIAGE RETURN/NEWLINE (\r\n). This means that the original program created text files with \r\r\n between lines, a minor text file corruption, not our original intention. The fix is to change the Python line terminator back to a solitary \n on line 30 and let the C library "do the right thing" for its respective platform. Also, rather than adding line terminators to each line in the file (string in the list) ourselves and sending those to the file with the writelines() method, the common best practice is to use the string join() method along with a single call to the file's write() method -- it performs faster and takes up less memory. We apologize for any confusion caused for readers new to Python and/or cross-platform issues.

    (major patch [diff])

    81 :: 3.6 : Core Tip : The word "lookup" should be in normal roman font, not Courier.

    82 :: 3.6 : Lines 28-32 : Due to the change in the code for Example 3.1 above on p. 80, these two paragraphs need to be replaced with:

    Now that we have the entire contents in memory, we need to dump it to the text file. Line 29 opens the file for write, and line 30 writes each line to the file. Every file requires a line terminator (or termination character[s]). The '\n'.join(all) takes each line of all (list of input strings), and join()s them together into one large string delimited by the NEWLINE character. That single string is then written out to disk with the file object's write() method.

    85 :: 3.8 : Exercises 3-6(b) : Shorten part (b) to read, "What do each contain after...."

    85 :: 3.8 : Exercises 3-7 : The spacing gap between the 1st row of potential identifiers is greater than for the remaining rows. It should be reduced to match the rest.

    Chapter 4

    93 :: 4.3.2 : Core Note : Boolean values : The bullet points for the numeric types (4 thru 7) should be indented.

    NEW
    99 :: 4.5.2 : In the first paragraph of this page, replace "Sections 3.5.5-3.5.7" with "Section 3.5.4".

    100 :: 4.5.2 : Core Note : Interning : Change range(-1, 100) to range(-5, 257).

    102 :: 4.6 : Table 4.4 : All instances of obj in the "Function" column should be in italics.

    104 :: 4.6.3 : Core Note : It is likely that the back ticks (` `) will be deprecated in a future version of Python (say 3.0).

    105 :: 4.6.4 : At the bottom of this page, there are 2 comments that both read as "# new-style class". Change the first one to "# classic class".

    110 :: 4.6.5 :: Table 4.5 : isinstance() is missing from the built-in functions section of this table. The two possible syntaxes are: isinstance(obj, cls) and isinstance(obj, (cls1, cls2,... clsN)). The description should read, "Determines whether an object is of a certain type or class of types." Finally, it returns a bool. Also, the description for type() should be changed to: "Returns given object's type object".

    NEW
    113 :: 4.8.1 : The top of this page should refer instead to Section 4.9, not 4.8.

    UPDATED
    116 :: 4.9 :: char or byte : Remove "or byte" from both the section title and in the sentence. (Python 3.0 has a byte type.)

    118 :: 4.10 : Exercise 4-9 : Change the middle pair of statements in the code snippet to: 

    c = 1000
d = 1000

    Chapter 5

    132-133 :: 5.5.3 : Modulus : We neglected to give a proper example of using the modulus operator. Add the following to the end of the subsection: "The modulus operator in Python is like that of C, the percent symbol (%), and here are some examples of using it: 
    >>> 5 % 2
1
>>> 8 % 4
0
>>> 6j-7 % 3
(-1+6j)

    NEW
    133 :: 5.5.3 :: Exponentiation : The final part of this subsection requires 2 changes:

  • The last text sentence, beginning with, "Note that 1 / 4 as an integer...", needs to be replaced with, "Although 1 / 4 can be viewed strictly as an integer operation, (beginning with 2.2) Python correctly coerces both to floats so that the operation can succeed:".
  • The code snippet immediately below should be replaced with: 
    >>> 4 ** -1
0.25

    NEW
    139 :: 5.6.2 :: Operational : It may be more clear in the math.sqrt() reference of the 2nd paragraph to use Python symbols instead of superscripts, so change it to: math.sqrt(num.real ** 2 + num.imag ** 2).

    NEW
    143 :: 5.6.2 :: Table 5.6 : Add footnote "b" for coerce(): "Deprecated in Python 3.0." Place the footnote marker "b" just after the closing parenthesis in "... num2)".

    NEW
    147 :: 5.7.2 : In the final paragraph, add "example" between "the" and "below", as in: "... Note in the example below...."

    NEW
    151 :: 5.8 :: Table 5.9 : In the last row of the table (for the bitwise OR operator), there are tiny superscripted "v" and "vv" characters next to the bullets that should be removed. (Oddly, these do not show up in Table B.3 on p. 1025.)

    153-154 :: 5.9 :: Exercises 5-9 and 5-17 : There is an extra space in exercise 17 between the 2**31 and the -1. It should be 2**31-1. The extra space needs to be put between the 017 and the + in the 2nd example of exercise 9(a), as in >>> 017 + 32.

    Chapter 6

    UPDATED
    167 :: 6.1.3 :: Table 6.3 :
  • Footnote "d" in the first column marking zip() should be in roman font, not Courier/mono.
  • For sorted(), add the following to the end of its description: "... built-in method (see Table 6.11 on p. 221)"

    NEW
    172 :: 6.3.2 :: Membership (in, not in) :

  • The 2nd sentence uses a wrong word and should read as: "... if that substring appears in the...."
  • The 3rd sentence uses a wrong word and should read as: "... used to determine where a substring is...."

    173 :: 6.3.2 :: Membership (in, not in) : The string data attribute names have changed. string.uppercase, string.lowercase, string.letters all have Unicode characters now. To get the pure ASCII versions, use string.ascii_uppercase, string.ascii_lowercase, string.ascii_letters.

    173 :: 6.3.2 :: Example 6.1 : Line 1 is missing the (root directory) first forward slash in the start-up directive; it should be, #!/usr/bin/env python, and line 5 should refer to string.ascii_letters.

    173-174, 246, 1014 :: 6.3.2, 6.2.2, Appendix A :: Example 6.1, Exercise 6-2, Answer to Exercise 6-2 : An extraordinary amount of emphasis is placed requiring possible identifier strings to be longer than one character in length when it is not absolutely necessary (as you are probably aware). The first part of Exercise 6-2 is not a "trick question" nor is changing the length check artificial. More of an emphasis should be placed on the 2nd half of the exercise instead. The solution given in Appendix A can be replaced by a simpler solution (which can be downloaded here). 
    #!/usr/bin/env python

from keyword import kwlist
import string

ALPHAS = string.ascii_letters + '_'
NUMS = string.digits

def main():
    print 'Welcome to the Identifier Checker v2.0'
    myInput = raw_input('Identifier to test? ').strip()

    if len(myInput) == 0:
        print "ERROR: no identifier candidate entered"
        return

    if myInput in kwlist:
        print "ERROR: %r is a keyword" % myInput
        return

    alnums = ALPHAS + NUMS
    for i, c in enumerate(myInput):
        if i == 0 and c not in ALPHAS:
            print 'ERROR: first symbol must be alphabetic'
            break
        if c not in alnums:
            print 'ERROR: remaining symbols must be alphanumeric'
            break
    else:
        print "okay as an identifier"

if __name__ == '__main__':
    main()

    NEW
    184 :: 6.4.4 : This section refers to Section 6.7.4 as that for Unicode when it should refer to Section 6.8 instead.

    NEW
    186 :: 6.5.3 :: raw_input() : Remove the first part of the first sentence in the final paragraph of this subsection. It should read as: "Strings in Python do not...."

    UPDATED
    188-190 :: 6.22 :: Table 6.6 :

  • string.center(), string.ljust(), and string.rjust() methods are missing a parameter. They should be updated like this: 
    string.center(width, fillchar=' ')
string.ljust(width, fillchar=' ')
string.rjust(width, fillchar=' ')
    Each description should be appended with, "; fillchar is the padding character". All 3 entries should have a (new) footnote "g": "New or changed in in Python 2.4."
  • The entry for string.join(seq) should be: "Merges (concatenates) a sequence seq of strings into a single string delimited by separator string."
  • The string.rsplit(str=' ', num=string.count(str)) method is missing: "Same as split(), but search backward in string." It should have a (new) footnote "g": "New or changed in in Python 2.4."
  • The signature for string.splitlines() is incorrect. It should be: string.splitlines(keepends=False). The description should be revised as: "Splits string at all line breaks and returns a list of each line without them unless keepends=True."

    NEW
    193-194 :: 6.7.1 : There is case inconsistency in the hexadecimal value for zero. Change one occurrence of "0X00" on each page to "0x00".

    NEW
    195 :: 6.7.3 : The first sentence should refer to "Section 4.8.2".

    199 :: 6.8.3 : In the first complete paragraph (starting with, "In order to make Unicode...), the last four sentences (starting with, "Both have string...") need to be replaced as follows:

    ... Both behave similarly. Due to many issues users are having with regards to moving between Unicode and ASCII strings, Python 3.0 will adopt a new standard where all strings are Unicode. A new bytes type will be added for those needing to manipulate binary data and encoded text.

    NEW
    200 :: 6.8.4 : The 1st sentence of the 2nd paragraph should say, "... may use one or two bytes to represent...."

    NEW
    202 :: 6.8.5 : The filename "unicode.txt" in the 2nd paragraph should be in Courier/mono font.

    NEW
    202 :: 6.8.6 : The 4th bullet point should say, "... encoding and decoding of Unicode strings...."

    NEW
    203 :: 6.8.6 : The 3rd bullet point in the middle of the page has 2 typos:

  • "Plane" should be "Plone"
  • Missing a comma right after "Django"

    204 :: 6.8.8 :: Unicode Type : "basestring" should be in Courier/mono font.

    NEW
    206, 351 :: 6.9, 9.10 :: Tables 6.10 and 9.7 : Replace "c/StringIO" with "{c,}StringIO"

    NEW
    207 :: 6.9 :: Table 6.10 : Remove the row for the no-longer-available rotor module.

    NEW
    214-215 :: 6.12.2 :: Concatenation ( + ) : Replace both references to Section "6.13" to "6.14".

    NEW
    218 :: 6.13.2 :: max() and min() : The code snippet at the top of the page should be replaced with: 

    >>> max(str_list)
'over'
>>> max(num_list)
619000.0
>>> min(str_list)
'candlestick'
>>> min(num_list)
-2

    219 :: 6.13.2 :: sum() : In the code snippet on the line that makes a call to the reduce() function, add a comment so the line looks like this: 
    >>> reduce(operator.add, a) # see Section 11.7.2

    NEW
    219 :: 6.13.2 :: list() and tuple() : The 2nd section has a wrong word: "list" should be "tuple", as in: "... the list you passed to tuple() does not turn into a tuple, and the tuple...."

    UPDATED
    232 :: 6.16 :: How to Create and Assign Tuples : Change "empty tuples" in the first paragraph to "tuples with only one element" -- see the example below with emptiestPossibleTuple which is also inappropriately-named since it is a tuple of a single element, not very empty at all -- change the name to singleItemTuple. Empty tuples are specified with just a pair of parentheses: ( )

    237 :: 6.18.3 : The colons (":") in foo1(), foo2(), and foo3() serve only as ellipses to indicate some random code for each of these functions... they are not valid Python syntax.

    240 :: 6.19 :
  • Fix this typo in the final paragraph of this section at the top of the page: "... also contains the same for sequence types." (This refers to the functional equivalents to sequence type operators.)
  • The final three sentences (beginning with, "Finally, the...") need to be replaced as follows:
    ... including sequence types. The re module is for regular expressions, the StringIO modules allow you to manipulate strings like files, textwrap is useful for wrapping/filling text fields, and collections has high-peformance specialized containers.

    NEW
    243 :: 6.21 : In the last sentence, add some text to explain the table shading: ".. function and methods (shaded in order of precedence) for sequence...."

    247-248 :: 6.22 :: Exercise 6-7 and Example 6.4 :
  • Example 6.4 is really 6.5. This should be fixed in the Exercise as well as at the top of p. 248.
  • On lines 10-27, change all occurrences of fac_list to non_fac_list.
  • On lines 11 and 27, change 'non_fac_list' to repr(non_fac_list) (removing single quotes).

    250 :: 6.22 :: Exercise 6-18 : This exercise requires corrections and should be replaced as follows:

    6-18. zip() Built-in Function. In the zip() example of Section 6.13.2, what Python object does zip(fn, ln) return that can be iterated over by the for loop?

    Chapter 7

    NEW
    256 :: 7.1 :

    NEW
    258 :: 7.1 :: Core Tip : Change part of the last sentence to read as: "Do NOT create variables with built-in names like:...".

    NEW
    259 :: 7.2.2 :: Dictionary Key-Lookup Operator : In the code snippet at the end of this subsection, change the comments so they read as: 

    d[k] = v    # set value in dictionary
d[k]        # lookup value in dictionary
    We should add one final paragraph in this section: "Although we can use d[k] to perform looking up a value in a dictionary using its key, this is not the safest way of doing so, as users will encounter KeyError if a key is not found in the dictionary. Better alternatives include using a dictionary's get() method -- this is an improvement because it allows the programmer to specify a default value to return in case the key doesn't exist. Another alternative is the dictionary setdefault() method -- similar to get(), it doesn't just return the default value but also adds that value to the dictionary using the (previously non-existent) key, hence its name of "setdefault".

    NEW
    261 :: 7.3.1 :: Dictionary Comparison Algorithm :

  • The first sentence that begins at the top of this page has swapped the references for dict1 and dict2. It should read as: "... when we get to the 'port' key, dict1 is deemed ... that of dict2's 'port' key...."
  • The final sentence in this section should state that, "[our] final example reminds us that...".

    266 :: 7.4 :: Table 7.2 :

  • The second entry should be dict.copy() not dict.clear().
  • These should be in Courier/mono font:
    1. The "*" in dict.iter*() (1st col)
    2. The "None" in dict.setdefault() (1st col)
    3. The "dict" in dict.has_key() (2nd col)
    4. Swap the rows for dict.keys() and dict.iter*() so as to correctly alphabetize by method name.
    Many of these errors are actually correct in (the equivalent entries in) Table B.9 on p. 1035.
  • NEW Add a new footnote "f" for the dict.has_key(key) entry: "Deprecated in Python 2.2 and removed in Python 3.0; use in instead."
  • Change footnote "b" to refer to Section 6.20
  • For dict.items(), dict.keys(), dict.values(), replace "a list" in all 3 descriptions with "an iterable", and create a new footnote "g" for all 3 that reads as: "The iterable is a set view starting in Python 3.0 and a list in all previous versions."
  • Change footnote "d" to read as: "New in Python 2.2 but removed in 3.0 because their non-iterator equivalents will return an iterable beginning with that release (also see "g").
  • Finally, ensure all necessary changes are made to Table B.9 on p. 1035.

    UPDATED
    267 :: 7.4 :

  • In the first sentence of the second paragraph (right below the code snippet), "directory" is the wrong word and should be changed: "... add the contents of one dictionary to another."
  • In the paragraph above the final code snippet replace the reference to Section 6.19 to 6.20.

    NEW
    270-271 :: 7.5.2 :: Example 7.1 :

  • This source code is missing all boldfacing of Python keywords, i.e., all occurrences of def, while, if, continue, else, break, print, not, try, except, in (outside of quotes, i.e., "try"). Specifically, they are lines 5, 7, 9, 11-13, 17, 21-24, 26, 35, 38-39, 41, 43-46, 49-51, and 53.
  • Lines 34, 49, 50, 51 should be indented to the same level as line 35.
  • Lines 41, 43, 44, 46 should be indented to the same level as line 39.

    NEW
    274 :: 7.6 : The top of the page features a sentence ending in "... integrated into Python 2.4." Insert this sentence immediately following that one: "The sets module is deprecated in Python 2.6." Also, change the text in the graphic logo in the margin to "2.3-2.6".

    NEW
    276 :: 7.7.1 :: Membership (in, not in) : In the 1st sentence, both "in" and "not in" should be in Courier/mono bold.

    NEW
    286 :: 7.12 :: Exercise 7-5 : In exercise 5(c), the parenthesized list should remove reference to the now-obsolete rotor module and add in a few new ones. It should be replaced with: "(see the getpass, md5, crypt [Unix-only], hashlib [2.5], and other cryptographic modules)."

    288-289 :: 7.12 :: Exercises 7-13 - 7-15 : In all 3 problems, all references to sets A and B should be in Courier/mono font, including any operators in between.

    Chapter 8

    295 :: 8.4 : Guido's name was messed up in the 1st and 3rd paragraphs during the final editing phase of the manuscript. Read as only "Guido" or "van Rossum", not "van Rossum Guido"[sic].

    303 :: 8.6.5 : There is a misspelling of "returning" in the final sentence of this paragraph. Also, so readers don't have to hunt for the reference, the final sentence should end with, "... similar to views as discussed in the previous chapter at the end of Section 7.4."

    NEW
    306 :: 8.8 :

  • In the code snippet, remove "# (or valid == 0)" on the line that starts with, "if not valid:".
  • The last sentence of this section should be edited as follows: "... variable remains False, which presumably...."

    NEW
    307 :: 8.10 :: Example 8.1 : Line 1 of the code should be in Courier/mono

    NEW
    308 :: 8.10 : Remove the last sentence in the paragraph starting with, "Likewise, a...".

    NEW
    317 :: 8.13 :: Cross-Product Pairs Example : Change "like" to "unlike".

    NEW
    323 :: 8.15 :: Exercise 8-13 : Change the beginning sentence of this exercise to, "In Section 8.6.2, we...."

    Chapter 9

    327 :: 9.2 :: Table 9.1 : Footnote "A" : Universal NEWLINE Support (PEP 278) was added in Python 2.3 not 2.5.

    NEW
    334 :: 9.3.6 : A colon (:) is missing after "doublespaced" near the top of the page. It should read as: "... display would be doublespaced: one NEWLINE...."

    338 :: 9.6 : In the first code snippet, the call to str() to convert sys.argv to a string is superfluous. print does it automagically.

    NEW
    341 :: 9.7 :: Table 9.5 :: File Descriptor Operations : In the description for open(), the "s" in the final word should be a closing square bracket, as in: "... built-in function]"

    Chapter 10

    NEW
    362 :: 10.2 :: ZeroDivisionError : "Our examples above used integers, but in general...."

    NEW
    374 :: 10.3.6 : In the 1st sentence of the 2nd-to-final paragraph on this page, the Chapter 13 title is wrong, so we can just replace it with a comma, as in: "... discover in Chapter 13, the special...."

    376 :: 10.3.7 :: Example 10.1 : cardrun.py
    The original installed script was out-of-date. Please download a new one if your file is older than 2007 Jan 1. We also installed the example carddata.txt file as listed on p. 375 as well as updated the alternate version in the alt directory. (critical patch)

    377 :: 10.3.7 :: Line-by-Line Explanation :: Lines 36-37 : The cat cardlog.txt command-line has an extra space that should not be there.

    NEW
    379 :: 10.3.9 : The except in the 1st sentence of the final paragraph of this section should be in Courier/mono BOLD.

    380-381 :: 10.3.10 : In the pair of examples using try-finally, if the open() call fails, ccfile will be undefined, resulting in a NameError exception being thrown, an insult to injury on top of the IOError exception we received for the failure in open(). The usual idiom to avoid this situation is by setting ccfile = None before the try-finally, then add an if ccfile: before calling close(), as in this replacement for the code on p. 380: 
    ccfile = None
try:
    try:
	ccfile = open('carddata.txt', 'r')
	txns = ccfile.readlines()
    except IOError:
        log.write('no txns this month\n')
finally:
    if ccfile:
        ccfile.close()

    and this replacement for p. 381: 

    ccfile = None
try:
    try:
	ccfile = open('carddata.txt', 'r')
	txns = ccfile.readlines()
    finally:
	if ccfile:
	    ccfile.close()
except IOError:
    log.write('no txns this month\n')

    384 :: 10.4.2 :: Context Expression, Context Manager : Italicize with_suite in the only paragraph on this page.

    386, 394 :: 10.5, 10.8 : In the final paragraph for section 10.5, we describe the obsolescence of string exceptions. The raising exceptions in Python 2.5 resulting in a warning can be further clarified that it will no longer be allowed in 2.6. Similarly, the catching of string exceptions results in a warning beginning in 2.6 but will not be allowed in 2.7.
    This clarification can also be carried to the second-to-last paragraph of section 10.8. It is erroneously stated that raising of string exceptions is not allowed in 2.5, which it is allowed but generates a warning. Similarly for the catching of string exceptions, it's really only disallowed starting in 2.7; in 2.6, a warning is generated.

    387-389 :: 10.6.1 including Table 10.1 : Italicize all the variables, such as with_suite, args, traceback, instance, exclass, tb.

    390 :: 10.7.1 : With regards to the __debug__ system variable, after Python 2.2, rather than having values of 1 and 0, it is a Boolean, thus have values of True and False, respectively.

    391-393 :: 10.8 : Table 10.2 : Various editing errors exist in the table of standard exceptions:
          • (391) The 2nd entry for SystemExit should have a footnote of "b" just like it is in the entry above. The entire row should also be grayed out, indicating the change that occurred back when Python 2.5 was released.
          • (392) (The 2nd entry for) KeyboardInterrupt should have a footnote of "c" just like it is in the entry on the previous page. The entire row should also be grayed out, indicating the change that occurred back when Python 2.5 was released.
          • (392) TabError should be indented... it is derived from IndentationError.
          • (393) UnicodeTranslateError should have a footnote of "i" (not "f").
          • (393) PendingDeprecationWarning should be one word.
          • (393) Footnotes "b" and "c": the word "subclassed" should be "derived from".
          • (393) Footnote "f" is a duplicate of "h" and SHOULD BE REMOVED. All remaining footnotes and corresponding tagged text should be adjusted accordingly.

    UPDATED
    396-397 :: 10.9 :: Example 10.2 :

  • Line 77 should read as: "file = tempfile.mktemp()
  • In (most releases of) Python 2.x, file() is a factory function, so rename all variables named file between lines 20-95 to fn.
  • On line 103, replace 'deli' with eachHost (remove single quotes too)
  • Enter your own hostnames on line 101 rather than using our test lab machine names. (critical patch)

    NEW
    404 :: 10.13 : Table 10.3 : Add a 4th row to this table for the traceback module whose description is: "Formatted display of traceback objects"

    UPDATED
    405 :: 10.14 : Exercise 10-5 : All five subproblems [parts (a)-(e)] should be aligned (flush) towards the left so that part (b) does not wrap. Also, the Python prompt (">>>") for part (e) should not be in bold and should line up flush with the line below it.

    Chapter 11

    413 :: 11.2.2 : Near the top of the page, in the calls to foo, both the standard calls as well as the keyword calls should be aligned properly.

    414 :: 11.2.4 :: Example : In the 2nd paragraph, remove the space in "binary operators/ operations".

    UPDATED
    417 :: 11.2.4 :: Line-by-Line Explanation :: Lines 30-41 : Replace the middle section of the code snippet on the 2nd half of this page as follows: 
    $ easyMath.py
7 - 2 = 5
correct
Again? [y]
8 + 1 = 9
correct
Again? [y]
10 - 7 = 4
incorrect... try again
10 - 7 = 2
incorrect... try again
10 - 7 = 5
sorry... the answer is
10 - 7 = 3
10 - 7 = 3
correct
Again? [y]
7 - 5 = 2
correct
Again? [y] n

    NEW
    432 :: 11.5.2 :: Default Function Object Argument Example : The end of this subsection is missing an entire Line-by-Line Explanation subsection. At the bottom of this page, append the following:

    Line-By-Line Explanation

    Lines 1-3, 29-30

    In this short application, we import the urllib.urlretrieve() function. The only thing this program does when invoked is to execute download().

    Lines 5-10

    firstNonBlank() looks for and returns the first non-blank line in the list of lines passed in.

    Lines 12-18

    firstLast() uses firstNonBlank() to find the first and last non-blank lines in the set of lines of a downloaded web page. We can make the open() call more clear by passing in a 2nd parameter 'r', as a flag to open the file for read. It uses firstNonBlank() to find the first non-blank line and then flips the web page upside down by calling the lines.reverse() method and uses firstNonBlank() again to find the last non-blank line.

    Lines 20-27

    download() takes a URL and procesing function object process that it will execute later on. The URL has a default of http://www that will only work if you have a host named "www" on your network. It is a default because it allows you to change your call to download() on line 30 so that you can pass in alternative URLs to download. Now when passing in a function object as process, be sure to leave OFF the "()". This is because you only want to pass in the function object, not call it. You will see the parentheses when you are calling it (as in line 27). Although we default to passing in firstLast(), it is also replaceable with something else if you so desire.

    NEW
    434 :: 11.6.1 : In the 1st code snippet on this page, the 2nd print statement should be changed to: 

    print 'formal arg2:', arg2

    NEW
    442 :: 11.7.2 : Table 11.2 : Add footnote "c" for reduce(): "Moved to functools module in Python 3.0." Place the footnote marker "c" just after the closing parenthesis in "...init])". Replace footnote "a" with: "Effectively deprecated in Python 1.6 and removed in Python 3.0."

    443 :: 11.7.2 :: Figure 11-1 : The "0" and "1"s inside the box representing the boolean function bool_func() should instead be represented by the Boolean values False and True, respectively. Those values will be integers only prior to Python 2.3.

    444 :: 11.7.2 :: filter() : The 2nd paragraph (right beneath the code snippet) mistakenly refers to having two functions, one of which is main(). (We removed this function, pushed the body out to the global part of the code but did not update the text. Rewrite this paragraph as:

          This code snippet contains a function odd() which returns True if the numeric argument that was passed to it was odd and False otherwise. The main portion of the snippet creates a list of nine random numbers in the range 1-99. [Note that random.randint() is inclusive and that we could have used the equivalent random.randrange(1, 100) which is recommended because it has the same calling convention as the built-in function range().] Then filter() does its work: call odd() on each element of the list allNums and return a new list containing just those items of allNums for which odd() returned True, and that new list is then displayed to the user with print.

    446 :: 11.7.2 :: map() : In the 1st sentence of the 3rd-to-last paragraph, "map()" should be in Courier/mono.

    NEW
    459 :: 11.8.4 :: Example 11.7 : Indent line 7 to be at the same level as line 9.

    NEW
    460 :: 11.8.4 :: Lines 6-9, 26-31 : Remove the extra word "a" at the top of the page.

    UPDATED
    465 :: 11.8.5 : Replace both print statements without a parameter... like this: 
    print bar()

    UPDATED
    469 :: 11.10.1 : Replace the 4-line code snippet in the middle of the page with: 

    from random import randrange
def randGen(aList):
    while aList:
	yield aList.pop(randrange(len(aList)))

    Finally, all three of the code snippets used in this subsection can now be downloaded here (as of 2006 Dec 6).

    470 :: 11.10.1 : In the final sentence of the 2nd paragraph, "you" is the wrong word and should be changed: "Without generators, your application code...".

    474 :: 11.11 :: Exercise 11-13 : Reword part (c) to: Discard mult() and use lambda instead.

    NEW
    475 :: 11.11 :: Exercise 11-19 : For some reason, this new exercise was not added, so pls do so here:
    11-19. Variable Scope. Earlier in the chapter (see Example 11.9 on p. 466), we left determining the output of scope.py as an exercise for the reader.
    a) Write down your best guess, then download the code and run it. Were you close? Explain where you were wrong and why (if applicable). Hint: first determine the total number of lines output by counting how many print statements will execute before trying to figure out the output.
    b) Line 11 in proc2() is currently blank... insert this statement (indented properly): global j. How does this affect the output (and why)?

    Chapter 12

    NEW
    484 :: 12.4.1 : In the 2nd line of the code snippet, remove the extra "[".

    485 :: 12.4.4 : In the section title, "Import" should be in regular roman (italicized) font, not Courier Italic.

    488 :: 12.5.4 : The final sentence of the second paragraph features a misspelling of impter.py filename.

    494 :: 12.7.1 : Towards the end of this section, the reference to __init__.py is horribly misspelled. It is supposed to be "init" surrounded by a pair of double-underscores.

    495 :: 12.7.4 : At the bottom of the page when importing G3.dial, there is an extra trailing "." that SHOULD BE REMOVED.

    502 :: 12.10 : Exercise 12-6 : Resolving various spacing issues in the example call, we get: newname = importAs('mymodule').

    Chapter 13

    508 :: 13.1 :: Classes and Instances : Missing a word in the 3rd paragraph which should read, "...because there would be no references...."

    NEW
    509 :: 13.1 :: Methods : The reference to Section 13.7 on page 540 in the 2nd-to-last paragraph on this page should refer to page 541 instead.

    515 :: 13.2.1 : The 2nd to last sentence in this section should end with "OOD" instead of "OOP", otherwise it reads like infinite recursion, or "Mr. Bunny's Guide To Java". :-)

    520 :: 13.4.1 : Since this section is optional (as per the previous section), there should be a "*" in front of the subsection title.

    524 :: 13.4.4 : Under Table 13.1, the first paragraph should start with the following: "In addition to the __dict__ attribute of the class MyClass we just defined above, we have the following:". Also, the print statement for MyClass.__dict__ SHOULD BE REMOVED since we already displayed the contents of the dictionary for both new-style and classic classes in the immediately preceding subsection (on the previous page).

    NEW
    530 :: 13.5.4 :: Core Note : All references to InstCt should be changed to InstTrack to match the output below.

    NEW
    531 :: 13.6.1 :: Core Note : In the last sentence of the 2nd paragraph of this Core Note, change "much" to "must".

    NEW
    537 :: 13.6.5 :: Access to Class Attributes : In the 2nd-to-last sentence of the paragraph, change "free" to "tree".

    NEW
    538 :: 13.6.5 :: Use Caution When Accessing Class Attribute with Instance : In the last sentence of the final paragraph, change "c.version" to "foo.x".

    543 :: 13.8.1 : In the TestStaticMethod example, the call foo = staticmethod(foo) should be dedented to the same level as the definition of the foo() function, e.g., 

    class TestStaticMethod:
    def foo():
	print 'calling static method foo()'
    foo = staticmethod(foo)

    553 :: 13.11.3 : In the SortedKeyDict example output, the supposedly sorted list when using keys() is out-of-order due to an error correction: "xin-yi" was misspelled as "hsin-yi", and the edit was made without reordering the list correctly. it should be:

    By keys(): ['hui-jun', 'xin-yi', 'zheng-cai']

    575 :: 13.13.2 :: Example 13.3 : time60.py
  • Line 7 needs to be indented (right) so it is lined up with lines 8 and 9.
  • Also change the documentation string for __init__.py to say "Time60 initializer since it's more of an initializer than a constructor. (minor patch)

    UPDATED
    586 :: 13.14 :: Single Underscore ( _ ) : Remove the "we" at the bottom of this page: "...of the new-style we attribute access...."

    NEW
    591 :: 13.15.2 :: Simple Example Wrapping Any Object : In the final code snippet in the middle of the page: change the middle part of the quote in the print statement to "... file %r, mode %r at ...". On the next 2 lines, remove the single quotes enclosing both f.name and f.mode, and also put "..." on the code line that starts with f.mode: ... f.mode, id(f.get()))

    603 :: 13.16.4 :: Descriptor Examples : In the middle of the page, the sentence that starts with, "Our final example...," should refer to Example 13.9 on the next page. Otherwise, you may think that it refers to the previous code snippet.

    603 :: 13.16.4 :: Descriptor Examples and Example 13.9 :: Lines 28-38 : The final sentence of this paragraph has several problems. Rewrite as: "Note that if you are using Python older than 2.5, you cannot merge the try-except and try-finally statements together (lines 30-38)."

    604 :: 13.16.4 :: Example 13.9 : descr.py
    For this code to work with Python 2.5 and newer, delete line 31. For this code to work with any version of Python, indent line 34 one level (four spaces to the right). For the __set__() method, the open() statement on line 29 should really be moved to the innermost try block immediately below it (between lines 31-32), and the succeeding except should also be monitoring for IOError — just like in the above __get__() method. Less importantly, name should not not have a default value as it does now on line 9. Below, we post two patches, one for users of Python 2.5 and newer as well as one for those using Python 2.4.3 and older.
    (critical patch [diff]; pre-2.5 patch [diff])

    607 :: 13.16.4 : Properties and property() Built-in Function : The last part of the final sentence in the first complete paragraph at the top of the page before the definition of the ProtectAndHideX class should be changed to the following: "... encrypting it by using the bitwise complement operator:". (The XOR operator is binary and not used in this example.)

    UPDATED
    609 :: 13.16.4 : Properties and property() Built-in Function :

  • DELETE the final two sentences at the bottom of the page, starting with the sentence beginning with, "We also use a function decorator...."
  • The code snippet above this paragraph needs to be corrected, the most important is the DELETION of the "@property" line (see below): 
    #!/usr/bin/env python
'ProtectAndHideX.py -- protect the "x" attribute'

class ProtectAndHideX(object):
    def __init__(self, x):
        self.x = x

        @property
        def x():
            def fget(self):
		return ~self.__x

            def fset(self, x):
                assert isinstance(x, int), \
                    '"x" must be an integer!'
                self.__x = ~x

            return locals()

        x = property(**x())

    We have made this change plus additional lines testing this code available here.

    618 :: 13.18 :: Exercise 13-3 : In the preliminary work paragraph, there is a missing single closing quote for the string '$1,234,567.89', and that string should be in Courier/mono font.

    UPDATED
    619 :: 13.18 :: Example 13.11 : moneyfmt.py
    Line 13 of __repr__() should be replaced with a call to repr(), i.e., 
    def __repr__(self):
    return repr(self.value)
    The original code, including the source in the download area, has return `self.value`, which is synonymous for now. The single backticks will be deprecated in Python 3.0.

    621 :: 13.18 :: Exercise 13-7 : The last part of the final sentence of this exercise should read as: "... this class in to Exercise 6-15.

    UPDATED
    622 :: 13.18 :: Exercise 13-9 :

  • In the descriptions of the enqueue() and dequeue() functions, replace both occurrences of "list" with "queue."
  • The last sentence of this problem should refer to Example 6.4.

    624-625 :: 13.18 :: Exercise 13-20 :

  • Part (c): Add a 4th bullet: "A pair of keyword arguments (hr=10, min=30)"
  • Part (e): Delete the last sentence that reads as "Make it so."
  • Part (f): The first and last lines of the code snippet are in a slightly larger font... make all 4 lines have the same sized font: 
    >>> thu = Time60(10, 30)             [ed. reduce font size]
>>> fri = Time60(8, 45)
>>> thu + fri
18:75                                [ed. reduce font size]
  • (Add a) Part (g): "Can we move the math-oriented code out of __add__() and into one of the other methods of this class? If so, which one and why would it make sense to do so?"
  • (Add a) Part (h): 'Add new code to support the "subtraction" of Time60 objects. Extra Credit: also support in-place subtraction.'
  • (Add a) Part (i): "Implement an __int__() method which returns an int representing the total number of minutes expressed by a Time60 object."

    625 :: 13.18 :: Exercise 13-21 : Like the errata above for the code on p. 609, the use of property() as a decorator does not work for any version of Python. There is also multiple typos in the "alternate syntax" (which turns out to be the only syntax that can be used). This problem should be completely rephrased as:

    13-21. Decorators and Function Call Syntax. Towards the end of section 13.16.4, we used the syntax "x = property(**x())" to create a property for the x attribute. How does this idiom, including the enclosed call to x(), actually create the property?

    Chapter 14

    630 :: 14.1 :: "lambda Expressions" : In the (sub)section title, "lambda" should be in normal roman font, not Courier.

    640 :: 14.3.4 : Add footnote "a" for section title right after "exec": "Changed to exec() built-in function in Python 3.0."

    641 :: 14.3.5 : Add footnote "a" for section title right after "input()": "Because of its security flaws, input()'s functionality is replaced by raw_input()'s (and raw_input() removed) in Python 3.0."

    644-645 :: 14.3.6 :: Creating Code at Runtime and Executing It : For those unfamiliar with the C shell and its descendants, you can change the % prompt to that of sh/bash: $. The first one is misindented too far... move it to the left to align it with the rest of the program output.

    648 :: 14.3.6 :: Conditionally Executing Code :: Example 14.2 :
  • Line 24 should be indented at the same level as line 25
  • Line 29 should be indented at the same level as line 21

    649 :: 14.3.6 :: Line-by-Line Explanation :: Lines 18-29 : There is an extra blank line in the program output... remove it.

    650 :: 14.4.1 :: Core Note : Near the end of the 1st paragraph, replace "def foo" with "def bar".

    651 :: 14.4.2 : Add footnote "a" for section title right after "execfile()": "Deprecated in Python 3.0; use exec() instead."

    651 :: 14.4.1 : The print statement for import2.py needs to be indented to the right one more space.

    652 :: 14.4.1 : In the final paragraph eval() should not be italacized.

    657 :: 14.5.2 : In the (sub)section title os.popen() should be in Courier font.

    661 :: 14.5.5 : The reference to os.system() at the top of the page should not be in boldface.

    661 :: 14.5.5 :: Replacing os.system() : Remove the import os line completely.

    662 :: 14.5.6 :: Table 14.7 : (Python 2.6) All text labeled as "/popen2" should be removed, i.e., "os/popen2.popen2()" should be changed to "os.popen2()" and maintain footnote "a". Apply this to all three such that only "os.popen3()" and "os.popen4()" appear in the 1st column of the table. Also delete footnote "b", replacing it with footnote "c", changing the footnote "c" for "subprocess.call()" to "b". The original footnote "b" for "os.popen4()" should revert to "a".

    663 :: 14.7.1 : SystemExit in the second-to-last sentence on this page should be one word.

    664 :: 14.7.1 :: Example "14.4" : Replace both references to "14.4" with "14.3". (There is no Example 14.4.)

    NEW
    668 :: 14.8 :: Table 14-9 : Add new footnote "d" for popen2: "Deprecated in Python 2.6; use subprocess instead."

    UPDATED
    668-669 :: 14.10 :: Exercise 14-1 : There should be 13 exercises in this chapter:

    669 :: 14.10 :: Exercise 14-9 (14-11) :
  • Extra Credit 1: The "os" module name should be in Courier font.
  • Extra Credit 2: The "-ef" argument of the functional style call should be parenthesized, as in: sort(grep(ps(-ef), root), -n, +1).

    669 :: 14.10 :: Exercise 14-11 (14-13) : Should refer to Example 14.2, not 14.4.

    Chapter 15

    697 :: 15.3.13 :: Example 15.1 : rewho.py
    f.readlines() in line 7 can be shortened to the file iterator f, as in: 
    for eachLine in f:
    (minor patch)

    NEW
    699-700 :: 15.4 :: Example 15.2 and Line-By-Line Explanation (Lines 14-22) : In lines 4, 17, 22 of the code, change "lowercase" to "ascii_lowercase". Correspondingly, change the last word of the first paragraph of this subsection from "string.lowercase" to "string.ascii_lowercase".

    Chapter 16

    719-720 :: 16.3.2 :: Table 16.1 : It would be nice if the 2nd column were reduced in size so that the methods in the 1st column don't wrap.

    UPDATED
    729 :: 16.3.7 :: Example 16.4 : Line 20 in tsUclnt.py should simply be "print data", as in: 
    print dataudpliSock.close()
    (critical patch)

    734 :: 16.4.1 :: Example 16.5 : Line 13 has a font size issue.

    740 :: 16.5.2 : In the 2nd paragraph, remove the hyphen from the call to clientConnectionFailed().

    742 :: 16.6 : Replace the final part of the final sentence with, "... we strongly encourage you to read ahead to Chapters 17 and 20."

    742 :: 16.7 :: Exercise 16-5 : The URL for the socket example has changed to
    http://docs.python.org/lib/socket-example.html

    745 :: 16.7 :: Exercise 16-14 : In the final portion of the exercise, change "i.e." to "e.g.".

    Chapter 17

    749 :: 17.2.2 : Figure 17-1 : The diagram was not drawn correctly to specification. Here are some fixes to repair it:
    1. Make the FTP client box bigger and make the FTP server box smaller so they are nearly the same size... there is no size differentiation between client and server, so the diagram should reflect that.
    2. Move "M (> 1023)" left just above the top solid line connecting the FTP client box and the Internet cloud, symmetric to where "M + 1" is below the bottom solid line.
    3. Move "ctrl/cmd" down so it's just above the top dashed line inside the Internet cloud
    4. Move "data" to be centered just below the bottom dashed line inside the Internet cloud
    5. Change "20 or" to "20 [active] or"
    6. Change "N (> 1023)" to "N (> 1023) [passive]"
    7. Delete "(Active)(Passive)"

    754 :: 17.2.6 : Example 17.1 : Line-by-Line Explanation : Lines 11-44 :

    1. (middle paragraph) Add one more sentence: "After the transfer has completed, we would then call loc.close()."
    2. (final paragraph) Strike "if it is there": "...we remove the empty file if it is there to avoid clutter...".
    3. (final paragraph) Add a new second-to-last sentence: "We should probably put some error-checking around that call to os.unlink(FILE) in case the file does not exist."
    4. (final paragraph) Change the final sentence to: "Finally, to avoid another pair of lines (lines 43-44) that close the FTP connection and return, we use an else clause (lines 35-42)."

    755 :: 17.2.7 : In the first paragraph after the bullet points, "creating" should be changed to "created".

    757 :: 17.3.3 : The first paragraph after the list of steps is missing a word: "...carbon copy of using the FTP protocol."

    758 :: 17.3.4 : Table 17.2 : In the entry for "xhdr", move the "[" back two characters, to, xhdr(hdr, artrg[, ofile])

    759 :: 17.3.5 : In the line of code that starts with, ">> Rounding like this...", remove one ">" so that it is "> Rounding like this..."; also, it appears either this line or the line above it has the wrong paragraph tag as there is a gap between these two lines... it should be single-spaced like all the others.

    762 :: 17.3.6 : Example 17.2 : Line 60 : Not really a correction but a note that Generator Expressions were added in Python 2.4, so if you are using 2.0-2.3.x, you will need to switch it to a List Comprehension by changing the parentheses to square brackets.

    765 :: 17.3.6 : Example 17.2 : Line-by-Line Explanation : Lines 57-80 : At the top of this page following the first paragraph of this section which began on the previous page, insert the following new paragraph which explains line 60.
    Line 60 is a generator expression. It works like a list comprehension only it does lazy evalution and does not build the entire results list when this line is executed. (The entire dataset, data, is already taking enough memory as it is!) Rather, each line is only processed when its turn comes up in the loop below on line 62. Generator expressions were added in Python 2.4, so if you are using an earlier release, the easiest fix while minimizing memory use is to add a new statement in between lines 62 and 63: line = line.rstrip(). If memory is not a concern, then just use a list comprehension instead (change the parentheses to square brackets).

    UPDATED
    772 :: 17.4.8 : Figure 17-3 : "POP3 (read)" should be changed to "POP3 (receive)"

    773 :: 17.4.9 : Add a mention of secure mail retrieval by splitting up and updating the final sentence: "Before we take a look at a real example, we should mention that there is also a poplib.POP3_SSL class which will perform mail transfer over a secure connection provided the appropriate credentials are supplied. Let's take a look...."

    784 :: 17.6 : Exercise 17-28(a) : Not really a correction, but add a... "Hint: see the mailbox module and email package."

    Chapter 18

    801 :: 18.5 :: Core Tip : In the 3rd paragraph, the setDaemon() method name should not have a hyphen/dash.

    802 :: 18.5 :: Table 18.3 : There shouldn't be any spaces around the = for the join() method's arguments.

    NEW
    809 :: 18.5.4 :: Example 18.8 : In mtfacfib.py, we create a function named sum() which hides/shadows the built-in function of the same name. If you do not wish this, then just rename it to something else, like mySum(), for example, and update lines 16 and 21 accordingly.

    811 :: 18.5.6 :: Table 18.5 : The table describing the attributes of the Queue module needs to be updated... stay tuned for the exact corrections/updates. The most important correction at this time is that the first entry should be categorized as "Queue Module Class", not "Function". Also, the "q" should be capitalized, as in Queue(size). For more details, see the module documentation at http://docs.python.org/lib/module-Queue.html

    Chapter 19

    NEW
    833 :: 19.3.5 :: Line-by-Line Explanation :: Lines 1-18 : The functional module is renamed to functools.

    834-835 :: 19.3.6 :: Example 19.6 : Lines 15 and 17 should be indented like the rest of the lines.

    851 :: 19.6 :: Exercise 19-2 : Replace "windows" with "widgets".

    851 :: 19.6 :: Exercise 19-4 : HINT: you will need 3 separate handlers or, customize one handler with arguments preset (still 3 function objects).

    Chapter 20

    860 :: 20.2.1 :: Table 20.2 : In the header for the first column, net_loc should be in Courier Bold Italic.

    UPDATED
    868 :: 20.2.4 :: Example 20.1 :
  • Change the name of this cile in the Example header to "urlopenAuth.py".
  • Change the login name from wesc to wesley so it matches up with the other examples in this chapter.
  • Adjust line 20 so it is flush with the other lines of code.

    869 :: 20.2.4 :: Line-by-Line Explanation :: Lines 24-29 :

  • Change the filename in the code snippet urlopenAuth.py (The current name [urlopen-auth.py] will not allow the module to be imported since '-' is not a valid Python identifier.)

    871 :: 20.3 :: Example 20.2 : The code for the __init__() and filename() methods (lines 16-17, 20-34) are not indented properly... there should be 4 spaces of indentation for these methods.

    878 :: 20.5.1 : The final line of code on this page is missing an optional parameter... it should read as: $ python -m CGIHTTPServer [port].

    879 :: 20.5.1 : In the final paragraph of this section (above the URL links), cgi-bin is accidentally titlecased twice.

    880, 890-892, 897-898 :: 20.5.2, 20.5.5, 20.7.4 : Figures 20-4, 20-9, 20-10, 20-11, 20-14, 20-15 : The captions should be centered so they fit on a single line below each figure.

    NEW
    885 :: 20.5.4 :: Example 20.5 : The if clause (line 49) should be indented at the same level as the else clause (line 51).

    896 :: 20.7.3 : In the first complete paragraph at the top of the page, string.split() should be str.split() to indicate usage of the split() method of strings rather than the split() function of the string module.

    911 :: 20.9 :: Table 20.7 : In the description for the wsgiref module, "application" should be in plural, e.g., "applications."

    913 :: 20.10 :: Exercise 20-3 : Remove the extra comma in the reference to Example 11.4.

    914 :: 20.10 : Exercises 20-10 and 20-11 : Exercises 20-7 through 20-10 are related and grouped together; there should be an extra blank line separating Exercise 20-10 and 20-11.

    Chapter 21

    928 :: 21.2.2 : Methods : Table 21.5 : Each of the arguments of errorhandler() should be in Courier Italic. There should also be some text just above this table which describes the error-handling mechanism further, such as, "An option for database adapter writers to allow for user-defined error handlers is available. Both Connection objects as well as Cursor objects (see next section) allow module authors to define an errorhandler() method for this purpose.

    929 :: 21.2.3 :: Table 21.6 : For the description attribute description, both name and type_code at the end should be in Courier Italic.

    UPDATED
    935-936 :: 21.2.7 :: MySQL : Remove all text starting at, "Keep in mind...", at the bottom of p. 935, all the way to the end of this section at the top of p. 936.

    937 :: 21.2.7 :: SQLite : The pysqlite database adapter should not be in Courier.

    939-945 :: 21.2.7 :: (Example 21.1) : There is no output for Example 21.1; however, we do provide the output of the equivalent ORM versions (twice) later in the chapter. The output of those applications will be the virtually the same, given the natural variations of the random numbers generated.

    940-953 :: 21.2.7-21.3.3 :: Examples 21.1-21.3 : In various places, the font was shrunk so as to not wrap lines. This may look strange in the text. These include the following:
          • Example 21.1: 54, 107-115, 136
          • Example 21.2: 56, 64, 75, 99
          • Example 21.3: 71

    941 :: 21.2.7 :: Example 21.1 : Line 55 should be flush with the others in this elif clause.

    947 :: 21.3.3 :: Line-by-Line Explanation :: Lines 33-44 : try-except should be in bold.

    953 :: 21.3.3 :: Line-by-Line Explanation : In the section for lines 79-80, there should not be a space between the function name and parameters in the getattr(orm, 'drop') call, and further on, self.users should be in Courier/mono font. Finally, there are too many blank lines above and below the next section (lines 82-84).

    Chapter 23

    987 :: 23.1.1 : Table 23.1 : Footnote "b" can be worded better: "Some values come back (additionally) quoted although all are returned as part of a single CSV string from the server."

    988 :: 23.1.1 :: Example 23.1 : stock.py
    Line 20 should be u.close().
    (critical patch)

    998 :: 23.2.5 :: Example 23.5 : olook.pyw
    For running the demo), the outlook() function should be named olook() (to match the name of the module) because that is what the demo expects. Since we are lazy, we just simply create an alias to the original function by inserting a new line 31 which reads: olook = outlook. If you're not going to run it, this change is not necessary.
    (minor patch)

    1001 :: 23.2.6 :: Example 23.6 : estock.pyw
    Line 43 should be u.close(). Also, on line 25, "as" should not be bolded.
    (critical patch)

    Appendix A

    NEW
    1012 :: Chapter 2 :: Exercise 2-7 : The 3rd solution for this problem, using a while needs to increment the variable otherwise the loop is infinite. Add the following line immediately following and indented at the same level as the print statement, i.e., 
    i = 0
slen = len(s)
while i < slen:
    print i, s[i]
    i += 1

    Appendix B

    NEW
    1025 :: Table B.3 : Footnote "b" should refers erroneously to Table 5.2... it should be Table 5.3.

    NEW
    1038 :: File Object Methods and Data Attributes : The section title has "Attributes" misspelled... remove the extra "o".

    CREDITS

    Thanks to the many readers who have provided invaluable feedback and corrections in this section. They include but are not limited to: David Librik, Sebastian Strempel, Loek Engels, Steven Wayne, Viraj Alankar, Johan Neven, Dave Hines, Barrett Shiff, Harold Trammel, Marie-Cécile Baland, Greg Nofi, Mark Ackerman, Tony Tang, Adil Lotia, Satoshi Tanabe, Raven Erebus, Tim Heaney, Victor Cosby, Dimitris Segounis, Paul Kippes, David Håsäther, Mike Driscoll, Dick Moores, Art Rathjen/Mary Bos, Boyd Brown, Paolo Palumbo, David Drysdale, and others.

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