I received a review copy of Mark Pilgrim’s updated `Dive Into Python
3`_ back in early November, but with the various holidays and
end-of-year activities I didn’t have a chance to read it until the
past week or so. I’m glad I waited until I had the time to sit down
and look over it carefully, because there is a lot of good material
Disclaimer: The review copy was free.
Inspired by Gene Ambaum and Bill Barnes’ review short-cuts, here’s
my review for the impatient reader:
Why I picked it up: Mark’s work has been the standard go-to guide
for learning Python for years now. I wanted to see what the new
version had to offer.
Why I finished it: No fluffy, contrived examples. Real-world code
and concise, clear discussion. And there’s no attempt to avoid
I’d give it to: Beginner to intermediate programmers who want to
learn Python or improve their existing Python skills and experienced
programmers who want to learn about the new features of Python 3.
Many of you may be familiar with DiveIntoPython.org, one of the
earliest major works published under an open license. The new edition
of the book has been updated to cover Python 3.1, including new
examples and entire new sections on language features not present in
earlier versions of the language. Starting with comprehensive setup
instructions to get Python installed, the introduction leaves no
excuses for not following along with the coding examples as you
read. It even includes advice for picking a text editor, in case you
don’t have one already.
Dives Right In
True to the title, the first code sample in Dive Into Python is a
complete program to convert integers to human-readable approximations
of different units. It uses I/O, dictionaries, functions (with
docstrings), new-style string formatting, and exceptions. On page 1.
Books about programming usually start with a bunch of boring
chapters about fundamentals and eventually work up to building
something useful. Let’s skip all that.
The more traditional discussion of integers, floats, strings, and data
structures is included early in the book, but that first example grabs
the attention better than the beginnings of many introductory texts.
Just the Facts
The explanation of that first program avoids fluff, staying on point
and addressing the reader as an intelligent learner. Striking that
balance between explaining the minutia of an example and letting the
reader discover the answer for themselves can be difficult, but Mark
finds it every time. This pattern is repeated throughout the book,
with each code sample being introduced, then examined in detail. Some
of the more important or interesting parts of the code are called out
for special discussion, as needed. And a few times sample code from
earlier in the book is reused in a later section. That code-reuse
reinforces the earlier point, while building on it to make the new
Throughout the book technical details about using Python (the language
and libraries) are mixed with solid developer advice on topics like
writing readable code, choosing tools, and getting the most out of
techniques such as testing. Chapter 14 covers HTTP web services, and
doesn’t stop with the basics of using httplib. In addition to talking
about third-party packages like httplib2, the chapter also stresses
the importance of creating well-behaved web clients and shows
techniques for doing so.
Beyond the Basics
The book also includes chapters on advanced topics such as porting
from Python 2 to Python 3 and packaging a library or application for
distribution. The porting chapter is actually a case study of porting
a real Python 2 library, chardet. It goes through the process of
running 2to3, and then works through examples of the conversion steps
that have to be done by hand. There’s a separate appendix with even
more detail about the types of automated translations 2to3 can make.
The more exotic your installation process is, the more exotic your
bug reports will be.
The packaging chapter stresses the need to follow standards and
conventions to make distributing your code easier – both for yourself
and and for your users. It covers the details of using distutils and
PyPI, licensing, and building source and binary distributions.
I can recommend Dive Into Python for any beginner or intermediate
programmer with a desire to pick up Python from scratch, or improve
their existing Python skills. More experienced programmers will find
the first few chapters fairly light reading, but the chapters on HTTP,
XML, and other advanced topics in the rest of the book helpful.
The porting and packaging chapters were of special interest to me.
This is starting to look like the year we should all be porting our
libraries to Python 3, so I imagine I’ll be re-reading the material on
2to3 a few times over the next few weeks.