Python Distilled

Welcome! This repo contains errata related to the Python Distilled book by David Beazley. If you'd like to contribute, please submit an issue or pull request.

Errata

Table 1.2, pg. 5. Description for round(a, [n]) should state that it rounds to the nearest multiple of 10 to the -nth power.
Section 1.6, pg. 10. Comment in code sample mid-page should read # g = 'Hello Cruel World'.
Table 1.6, pg. 10. Description for s.endswith(prefix [,start [,end]]) would be better if it used suffix instead of prefix.
Section 1.8, pg. 15. ['SYM', '123', '456.78'] should include the newline and be ['SYM', '123', '456.78\n']
Section 1.10, pg. 17-18. There is somewhat inconsistent use of variable names in this section. The names1 variable should be s and the names2 variable should be t.
Section 1.15, pg. 26. print "Going away..." should be print("Going away...")
Section 2.1, pg. 38. Typo mid-page should read "Tuple, list, set, and dictionary literals are written as follows:"
Section 2.7, pg. 43. Truthiness should be expanded to include sets and any non-empty container. "... any nonzero number, a nonempty string, list, tuple, set, dictionary, or container is taken to be true."
Section 2.7, pg. 44. The function invocation of foo(3, a) should be f(3, a).
Section 2.14, pg. 52. The list comprehension example should use squares instead of nums.

nums = [1, 2, 3, 4, 5]
squares = [ ]
for n in nums:
    squares.append(n*n)

Section 2.15, pg. 55. The code example should use slicing t[:1] instead of indexing t[0] to avoid a possible IndexError exception.

comments = (t for t in lines if t[:1] == '#')   # All comments

Section 4.8, pg. 88. compute_cost(prices, quantities) should be compute_cost(prices, units).
Section 5.8, pg. 106. The docstring in the factorial() function should use factorial(5) instead of factorial(6) to get a result of 120.
Section 5.16, pg. 121. The first function signature for after() should be changed to the following:

def after(seconds, func, /, *args, debug=False, **kwargs):
    ...

Section 6.4, pg. 145. The code for print_matching() should be as follows:

def print_matching(lines, substring):
    for line in lines:
        if substring in line:     # line instead of lines
	    print(substring)

Section 7.1, pg. 153. An extra line should probably be added to the example to show the effect of mutation:

>>> names[1] = 'Tom'
>>> names
[ 'Paula', 'Tom', 'Lewis' ]
>>>

Section 7.3, pg. 156. Missing right parenthesis on b.withdraw(50.0).
Section 7.7, pg. 160. Perhaps the class should be called MyAccount instead of MyAcount. Although, it's inheritance--you can call the class whatever you want!
Section 7.12, pg. 172. Comment in code right before section 7.13 should read # Calls Date.today(Date).
Section 7.21, pg. 194. The code for register_decoder() should use mt instead of mt.mimetype. For example:

_registry = { }
def register_decoder(cls):
    for mt in cls.mimetypes:
        _registry[mt] = cls
    return cls

Section 7.23, pg. 200. Typo in constructor example at the top. Should be

a = Account.__new__(Account, 'Guido', 1000.0)
if isinstance(a, Account):
    a.__init__('Guido', 1000.0)

The example that follows should also be corrected to:

a = Account.__new__(Account)
a.__init__('Guido', 1000.0)

Section 7.23, pg. 200. Typos in the date today() constructor. Should be

@classmethod
def today(cls):
    t = time.localtime()
    self = cls.__new__(cls)    # Make instance
    self.year = t.tm_year
    self.month = t.tm_mon
    self.day = t.tm_mday
    return self

Section 7.23, pg. 201. NOT a typo. The __new__() method of a class is, in fact, properly defined as a @staticmethod even though it looks like it ought to be a class method. This is strange, but you can see this in examples where __new__() is invoked directly. For example, a = Account.__new__(Account) on the previous page. Here, Account is passed directly as the cls argument as would be required with a @staticmethod.
Section 7.26, pg. 208. Typo (missing "that"). "A proxy is an object that exposes..."
Section 7.28, pg. 212. del f.owner should be del a.owner in example.
Section 8.7, pg. 234. It should be noted that the PYTHONPATH environment variable is a colon-separated list of paths.
Section 8.14, pg. 241. Typo ("is" should be "if"). "For example, if your package looks like this:"
Section 9.3, pg. 250. format(x, '<*10.2f') should be format(x, '*<10.2f').
Section 9.3, pg. 250. "The general format of the format specifier should be [fill][align][sign][0][width][,][.precision][type] where each part enclosed in [] is optional."
Section 9.3, pg, 252. 'Value is {val:<*10.2f}'.format(val=x) should be 'Value is {val:*<10.2f}'.format(val=x).
Section 9.3, pg, 253. Comment in code sample at bottom third of the page should be changed from # b'The value is 123.46' to # b'Value is 123.46'.
Section 9.9, pg. 264. for filename in path.Path('dirname').glob('*.txt') should be for filename in pathlib.Path('dirname').glob('*.txt').
Section 9.15.9, pg. 279. Typo, missing "to" in the sentence "Go to a directory with a collection of files and type the following:"
Section 9.15.12, pg. 281. Typo in code comment ("one" should be "once").

# Configuration of logging (occurs once at program startup)

Section 9.15.15, pg. 283. There is an extra return pathname.stat().st_size statement that can be removed (because there is a return statement right above it).
Section 9.15.19, pg. 285. serv should be server in the SMTP example:

server = smtplib.SMTP('localhost')
server.sendmail(fromaddr, toaddrs, msg)
server.quit()

Section 9.15.21, pg. 288. The output of struct.pack() should be as follows:

>>> struct.pack(">HIff", 123, 456, 1.23, 4.56)
b'\x00{\x00\x00\x01\xc8?\x9dp\xa4@\x91\xeb\x85'
>>>

Section 10.1, pg. 308. The description of round() should start with "Returns the result of rounding the floating-point number..."
Table 10.9, pg. 311. The description for format_map() should use "taken" instead of "taking". "Formats s with substitutions taken from the mapping m."
Table 10.10, pg. The description for s + t should read "Concatenation if t is a tuple."
Table 10.10, pg, 313. The s.append(x) method should be deleted.

Acknowledgements

The following individuals have contributed errata:

Jonathan Oberländer
Lucas Plaetevoet
Chris Gibson
Lawrence Wu
Andy Lester
Siavash Tavakoli
Said van de Klundert
David Dyck
Scythal
Feng Guo
Xavier Noria
Evan Friedenberg
Karthik-d-k
Marc Hertzog
Jack Rubin
Paul Barry
@physadair
@phils4000
@michrag
Sam Kramer
@wildekat
Shivam Parke
Olivia Nelson
@occoder
@yatcui

dabeaz / python-distilled

Python Distilled

Errata

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