Dive Into Python 309
| Dive Into Python | |
| author | Mark Pilgrim |
| pages | 432 |
| publisher | Apress |
| rating | 9 |
| reviewer | Joey deVilla |
| ISBN | 1590593561 |
| summary | The "desert island" Python book |
However, from time to time, you can find a programming language book that stands apart. You can tell from the way the author writes, the topics s/he covers, the unique presentation style and insight that s/he brings that the book is a labor of love. These books enjoy placement on the shelf closest to my desk -- that is, if they're not propped open beside my computer. Dive Into Python is such a book.
One thing that sets Dive Into Python apart from many other programming language books is that its author, Mark Pilgrim, didn't originally plan to make any money from it. As we often say in Open Source circles, he simply had an itch and decided to scratch it. Mark explains this in a story on his weblog in the form of a dialog between him and his manager after showing him a rough 20-page draft:
Manager: "This is really good. You could probably make some money off this someday."
Mark: "Maybe, but I'm not going to. I'm giving it away for free."
Manager: "Why would you do that?"
Mark: "Because this is the way I want the world to work."
Manager: "But the world doesn't work that way."
Mark: "Mine does."
First released in late October 2000 and published in online and downloadable forms under the GNU Free Documentation License, Dive Into Python had grown in fits and starts until 2003, when Mark declared the project closed. Even as an unfinished work, it was held in such high regard by the Python community that developers consistently recommended it; it was also included with ActiveState's Python and FreeBSD's ports distributions. When Mark announced that Apress had decided to pay him to finish the book and publish it, it became the most-anticipated book on Python ever. Even better, Apress has been gracious enough to allow Mark's world to work way it always has: Dive Into Python is still available for free download and is still under the GNU FDL.
What's in Dive Into Python
Many programming language books follow what I like to call the "Computer Science 101 Format", with the first few chapters devoted to covering basic concepts that any moderately experienced programmer already knows. Whenever I leaf through such a book and encounter a chapter that tries to reintroduce me to data types, looping or branching, I feel cheated; I'm essentially paying for a big chunk of book that I'll never read. If you've ever been annoyed by such filler, you'll find Dive Into Python a refreshing change. Rather than wasting time and trees devoting whole chapters to rehashing Computer Science 101, Mark chose to build each chapter after the first around a program that illustrates a number of Python features and programming techniques.
The programs upon which Dive Into Python's chapters are based strike a carefully-maintained balance. They are rich enough to illustrate a number of points and be the basis for some "real world" code, yet small enough to be comprehensible tutorials. For example, chapters 2 and 3 are based on "Your First Python Program", which is a mere six lines of code. However, in those six lines, you are introduced to function declarations, documentation strings, objects and their attributes, importing modules, Python's indentation rules, the "if __name__" idiom, dictionaries, lists, tuples, string formatting and list comprehensions. Within the first hundred pages, a point where many books are re-acquainting you with the "else" keyword, Dive Into Python covers the aforementioned topics as well as Python's reflection capabilities, list filtering, the "and-or trick", lambda functions, OOP and exception handling, all with enough thoroughness to be useful. After reading Dive Into Python, you may have trouble reading other programming language books because they'll seem glacially slow and fluff-laden in comparison.
For the first two-thirds of the book, Mark continues with this approach, presenting a program and then analyzing it to see what makes it tick, teaching Python and oftentimes a programming technique along the way. Each program covers useful tasks that you're likely to run into while programming and does so in an interesting way. At the same time, concepts are introduced in a way that makes sense. For instance, chapter 4 covers two topics that mesh together quite well -- exceptions and file handling -- and it does this by exploring an interesting application: a program that displays the ID3 tag information about each file in your MP3 collection. Later chapters explore regular expressions, HTML and XML processing and Web services. By the time you've finished the first two-thirds of Dive Into Python, you'll have been introduced to enough Python to start writing a wide array of "real world" applications. The book might have benefited from having a chapter covering database access, a task that's at least as common or as useful as accessing Web services, but that's a minor complaint.
While the first two-thirds of the book concerns itself with helping the reader become a Python programmer, the final third is about elevating Python programmers above mere competence. It covers useful topics (albeit rarely-covered in language books) such as refactoring and performance optimization as well as ones that may be new to even some experienced programmers: unit testing, functional programming and dynamic functions. Each chapter in this section is still based on an example program, but rather than analyzing a completed program, its evolution is traced. Although you can get by as a Python programmer without ever reading the material in this section, you'll be a much better one for having done so.
In keeping with the spirit of Python, Mark writes the chapters to present the material as completely and clearly as possible without extra clutter. If there's any additional material that doesn't apply directly to what he's trying to explain, he provides references or links to that material rather than attempting to "fatten up" the book.
The book's long gestation period, assisted by years of reader feedback and James Cox's editing has paid off. It doesn't have the rushed feel that many language-of-the-moment books have (especially the ones written by an army of authors, each one taking a chapter). As far as I know, there isn't any of the sloppiness that pervades many programming books these days, save one instance of the popular typo "teh" (and really, what truly 1337 book doesn't have one of these?).
Mark is aware that Python is likely not to be the reader's first programming language; it's more likely to be some descendant of ALGOL (or more precisely, a language that borrows heavily from either C or BASIC). He also knows that many programmers tend to misapply techniques from the languages with which they're familiar to the language they're learning. With these in mind, he's taken great care to introduce Python idioms as soon as possible. If you follow his advice, you'll be writing "real" Python and taking advantage of what the language has to offer rather than just writing Python-flavored version of whatever programming language you're most comfortable with.
Dive Into Python's Audience
The "user level" specified on the back cover of this book says "Beginner - Intermediate", which I feel is a little misleading. As I mentioned earlier, the book takes great care not to rehash topics with which programmers with some experience are already familiar and is written with the assumption that the reader is proficient in at least one object-oriented programming language. I think many programming novices would be overwhelmed with the speed with which Python features are introduced.
Experienced programmers, whether they are new to Python or are fluent with the language will benefit the most from the book. One programmer I know works with Python daily and and even submitted a patch to wxPython; even he said that Dive Into Python showed him things about Python that he never knew. If you're tired of books aimed at "Introduction to Computer Science" students, you're going to love this book. This doesn't mean that people who don't normally program can't benefit from the book: Joi Ito, who is a tech entrepreneur and not a programmer, learned enough from Dive Into Python to put together jibot, a bot for the IRC channel that bears his name. If you're new to programming, you might want to make Dive Into Python your second book or supplement it with an introductory text such as Apress' own Practical Python, O'Reilly's Learning Python or the free online book How To Think Like a Computer Scientist (the Python edition).
ConclusionDive Into Python may be one of the thinnest programming language books on my shelf, but it's also one of the best. Whether you're an experienced programmer looking to get into Python or grizzled Python veteran who remembers the days when you had to import the string module, Dive Into Python is your "desert island" Python book. If you're new to programming but have heard all the wonderful things about Python, make sure that this is the second programming book you read. My congratulations to Mark Pilgrim on an excellent book and authorial debut!
(Remember, you don't have to just listen to my effusive praise. Dive Into Python is available for free at diveintopython.org. Read it for yourself and if you like it, vote with your dollar!)
You can purchase Dive Into Python from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Don't forget the author's website (Score:5, Informative)
Re:shrinking shelf space (Score:2)
Ok, I'll bite... (Score:3, Insightful)
Instead of working for the man, Mark did what he wanted to do. Now the 'FLOSS-zealot' has written a well-respected book and the manager looks like a selfish loser.
I'd rather be a well-respected author than a manager with no imagination.
Seems like Mark decided to be the change he wanted in the world. Good for him.
Broken Link (Score:5, Informative)
'a mere 6 lines'? (Score:4, Funny)
Re:'a mere 6 lines'? (Score:4, Funny)
You're thinking of APL. Perl would take you at least 16 characters.
Re:'a mere 6 lines'? (Score:2)
Re:'a mere 6 lines'? (Score:2, Funny)
Re:'a mere 6 lines'? (Score:2, Funny)
http://p-nand-q.com/humor/programming_la
Re:'a mere 6 lines'? (Score:2)
Re:'a mere 6 lines'? (Score:3, Informative)
No, really, writing a lot of code in very few characters or lines is not the target, it is not good practice, it only makes code fuzzy.
Finally! (Score:5, Interesting)
Great Book (Score:5, Interesting)
This book, Python in a nutshell, and the online python library reference are the 3 tools that I always recommend for python newbies
Not suprising; I hope the book's good (Score:4, Interesting)
(I hope the author makes enough money - I just want to point out a possible reason for doing that kind of thing).
From the article I noticed one interesting thing - his world didn't quite work out until that company chipped in some money for him to finish the thing.
The same is with music and software - if it weren't for companies and/or sponsors....
Just in case the site crashes, you should be able to get the book via eMule( "diveintopython" the current version is 5.4.)
Re:Not suprising; I hope the book's good (Score:4, Interesting)
a) stop doing altogether
b) keep maintaining but not work actively on
c) spend his 'new-found' time on.
I believe the Diveintopython project was put in group a). So IIRC this would mean that APress gave him an offer to finish it after he chose to abandon the project himself.
I could be mistaken but I'm too tired to check his site now.. You do it
Re:Not suprising; I hope the book's good (Score:4, Interesting)
Dive into Python has always been a good book for some time now. The difference is that now it is available in a dead tree version, and it has had some professional editting.
His world worked out just fine. In fact, his free edition was good enough that he's getting paid to make a dead tree version while still giving away the electronic version.
It just goes to show that there is money to be made in this kind of stuff. Not huge piles of money probably, but enough to make it worth your while.
Re:Not suprising; I hope the book's good (Score:4, Interesting)
|>oug
Re:Not suprising; I hope the book's good (Score:2)
If writing a book like that could get me $60K a year kind of job, I'd write one for free too.
(I hope the author makes enough money - I just want to point out a possible reason for doing that kind of thing).
I'd bet the money making part is one level of indirection from writing the book.
That is, when you put out a resume looking for consulting jobs, etc. being able to list yourself as the author of a widely-recognized and lauded work is helpful.
a series of well planned coincidences. (Score:2, Interesting)
i've been meaning to get further into computer programming than the basic knowledge i already have, and this book seems worthy of a purchase. i have suffered through quite a few "intro" books that do little more than teach how to code math equations and silly text manipulations.
what i am really in
Re:a series of well planned coincidences. (Score:5, Informative)
Re:a series of well planned coincidences. (Score:2)
Re:a series of well planned coincidences. (Score:5, Interesting)
Inadvertantly, you question strikes to the core of modern IT, it is not language specific, but it is the root driving force behind all "geeks".
For too many people, the "Why-to" is "because I heard you can make lots of money as a programmer". To answer this demand, colleges and universities churn out rank and file incompetent and ambivalent programmers, weilding their Microsoft inspired toolchest of Visual Basic 6 or MS Access, they flood the resume pool, and pollute the code base with their lazy half-hearted attempts at development, causing project failures and frustration on a massive scale and dramtically increasing the costs of corporate IT.
These are the type of programmers who react with anger and fear when anyone mentions exploring different languages or technology. Who, when confronted with a problem or issue they don't understand are willing to shrug and say "I don't know" and pass the problem off to the true "geek" on the team.
On the other hand, you have the type of coder to which the "Why-to" question is like breathing... to whom coding grants god-like powers of creation, who is willing to stay up late solving obscure problems just for the rush of satisfaction when s/he gets the answer.
To this type of coder, the question is not so much "Why-to" but more, "How could I not?". Coding is not a job, it is a system of thought, the logical structuring of the chaotic real-world into discrete lines of code.
To this type of programmer, there is nothing more exhilarating than a new project, a blank file, a clean slate, from which they can craft the perfect solution. Starting from scratch and creating from nothing is the ultimate expression of their intellect, and they judge themselves critically by the result.
This is a quality that can not be taught in a univeristy, or measured by a multiple choice exam. These are the "basement geeks" who clutter their shelves with gadgets and obscure books.
They may have started on the IRC with the classic question "How do I make a game?", or as a sysop of a dial-up BBS who needed to add functionality.
The point is, for the true coder, the "Why-to" question was answered BEFORE the language question... they had some sort of need that could only be solved by learning to code... and after that they were hooked. They constantly evaluate new languages and more effecient/elegant methods of solving their problems.
There is no book that will make you _want_ to code, first you want to code _then_ you buy the book.
Asking "Why should I program?" is similar to picking up a shovel and saying "Why should I dig?". Unless you have a need, there is no point, and you will never understand why all those ditch-diggers keep debating the finer points of different shovels. You are out of context. For you, the answer is "You shouldn't".
That is, until you need a ditch.
My 2 cents (Score:5, Insightful)
Re:My 2 cents (Score:2, Interesting)
I went berserk for Ruby first, in much the same as people here for Python..I think my first script in it was an irc quiz bot. But for more advanced things than simple parsers, I like Python better. It's also faster and has a lot more support in the form of wrappers for other libraries. I pretty much gave up on Ruby now, although it's a pretty language.
I'm quite sure you can do the things at the end of chapter 17 in Ruby too though, they're very similar in that respect
Re:My 2 cents (Score:5, Interesting)
If whitespace has no meaning, then why does your code include whitespace?
Re:My 2 cents (Score:3, Interesting)
And anyhow, every programmer knows the difference between a space and a tab. And that neither one is "nothing". Anyone who tells you otherwise should try looking at C code written by hardware engineers someday (NO indentation at all).
The beauty of Python is that merely doing the responsible thing -- indenting your program -- makes it work. Someone who wants to "just make it work" (like, for example, a hardware programmer modifying C code) will automatically write approachable code;
Re:My 2 cents (Score:3, Interesting)
The surprise factor of mixing tabs and spaces can be annoying, too.
I've come to like Python a lot and I do most of my coding in it now, but I still think the i
Re:My 2 cents (Score:5, Funny)
Yes. Actually, it turns out the code's been in Python for a long time, but Guido only recently started documenting it, and like the metaclass hack, it has a lot of untapped potential.
Unlike the metaclass hack, it's surprisingly simple.
Here's a typical Python function in the old style:Here's one using a bit of the new, optional syntax:As you can see, this offers all of the advantages of curly braces. In fact, it only starts here. There's much more; so powerful are these "hash" prefix characters that they can be used to form other languages' block delimiters as well. Here's some examples:
Ada:Ruby:A plethora of possibilities is present. Alliteration initially unintentional.
Some are working on making the "hash" syntax marker work with natural language, to form a type of code documentation we're calling "comments" (named after a similar, rarely used construct that appeared in Fortran-77). These people are misguided, of course, and such constructs will certainly never be widely used; but in theory such capabilities would add a lot to a language.
-Billy
I dove into python... (Score:5, Funny)
Joy of programming... (Score:5, Interesting)
I was blown away. Having never touched the language within a couple of hours of going through the online documents I had picked up enough to write the full script. Once that was done I didn't want to stop. I found Python to be an absolute wonderful language that made programming fun again. Since then I've written my fair share of Python apps to do nearly everything. Infact anytime I need a program that I can't quickly find or isn't out of it's realm, it gives me an excuse to use Python. A lot of the time I lookup a way to do something and sit there smiling to myself going "now thats freaking cool".
I haven't read this book, but from my experience Python is an awesome language. I'm sure the Perl people feel the same way about their language. To me Python feels clean, flexible and productive. Most importantly its fun.
Re:Joy of programming... (Score:2, Funny)
You're either a masochist, or this was some form of cruel and unusual punishment. Perhaps you could enlighten us as to why someone would willingly subject himself to UF's brand of mind-numbing "art" (requires quotes because I can't call it real art with a straight face) and "humor" (same reason for the quotes).
Re:Joy of programming... (Score:2)
Re:Joy of programming... (Score:5, Interesting)
Basic, Fortran, Assembly (Intel and Sparc), Pascal, C, C++, Java, Lisp, shell(sh,awk,sed), Perl, and most recently Python. (roughly in that order; I saw some COBOL code once when a young programmer, but was immediately repulsed - thank heavens)
I actively use Perl and Python myself for everything now for several reasons:
1. All of the machines at my job (800+) are all preloaded with Perl - so I have to use it for automation (better than shell scripts particularly for mission critical one-off applications that have to be fault tolerant but deployed at the whim of our marketing and operations staff). If I didn't have to maintain Python myself on all of those machines, I would port everything over to Python in a heartbeat. However it took me 2 years to get management to agree to loading Perl in the first place - and there is no reason to incur the costs associated with validating a new scripting language for use in our production environment. So I live with it - and keep the footprint small.
2. For all other tasks - I use python.
Some neat things fall out of python [python.org] that even as a neophyte I can appreciate:
a) clean syntax (if I only had all the time spent finding dangling semicolons in perl, I could take a sabbatical)
b) full featured web development tool (Zope [zope.org] - provides a framework for developing and hosting full service applications - designed to make building products to run under Zope easy - seperates the presentation from the logic using ZPT cascading style sheets and DTML for presentation, and python for the program logic [unless you are masochistic enough to depend upon DTML alone] - has a built-in database for managing Zope objects - and built-in httpd and ftpd servers - which can be further frontended using Apache as desired - can communicate with other databases [oracle, ODBC, postgreSQL, etc... many database plugins available] - has a large library of predeveloped products [modules for you perlmongers] that you can load and be up and running, or modify to your heart's content - and did I mention that its GPL'd?)
c) platform independent (just as with java and perl, python scripts can run without modification on many operating systems - keeping porting costs down to a bare minimum.
d) built-in documentation functionality - not as full featured as Perl's perldoc - but I might not have found the right product yet to do that (ideas anyone? or, is this a python project waiting for me to jump on - perhaps something that ouputs XML?)
The only drawbacks (and I use this term with trepidation - because they can seem positively refreshing after 10 years with perl) that I can see are:
A. Does not have the sheer amount of user contributed products (modules) when compared to CPAN^ [cpan.org]. Of course I wouldn't judge the quality of my carreer based on the weight of all of my program printouts either. Quantity does not equate to quality.
B. Slower than Perl and Java. Again, something I can throw hardware at to rectify. Squid goes along way to making web pages generate faster too - so you can ameliorate some of the problems without having to kill yourself.
C. Sometimes it takes longer to find resources online than with other languages because of the difference in popularity. However, the time spent needing to refer to reference material for Perl and Java is many times larger than the time spent doing the same with Python.
D. Because of my long experience with Perl, I find myself immediately jumping to a predetermined algorithm/function that is implemented differently in Python and thus create syntax errors in my code. This last is really a personal problem that time will erase.
My whole programming paradigm has changed. The advent
Python: The Movie (Score:5, Informative)
Video: Introducing Python [ibiblio.org]
Features GvR, ESR, etc.
It's so bad it hurts. You'll want to show it to all your friends.
Re:Python: The Movie (Score:2)
Oh come on. I think t was really funny. Note that this movie was aimed for high-school kids.
Re:Python: The Movie (Score:4, Funny)
Re:Python: The Movie (Score:2)
Downloaded and loved (Score:2)
This book is quite good, although the PDF has odd little gray icond behind some of the text for some reason. It doesn't bother me really but I'm not sure what their for.
The book does have some great chapters and some not so hot ones but it's probably not the best read if you don't already have some Pygramming (that's Python Programming) experiance.
Lots of fun and by far one of the
Re:Downloaded and loved (Score:4, Interesting)
PyObjC is a start, but the little differences in how things are implemented between Python and Objective C makes using it a bit difficult to learn. Plus it's mac-only. Pyrex looks interesting but I've yet to try it. PyPy seems to have been in development forever.
For starters, I think the distutils module needs an option to produce a package/binary that is runnable on any similar machine whether python is installed or not.
Python is amenable to a variety of programming styles, is very readable, has well developed libraries, and is quick to write. But I've found myself wanting more than it can deliver, in terms of raw speed and number-crunching power, and even occasionally the need for typing and assignment by reference. I hope they find some way to deliver it someday, or make a language that retains the ease and efficiency of python but is also compilable.
Python Compiler (Score:2)
Re:Python Compiler (Score:3, Informative)
Re:Python Compiler (Score:2)
As for writing C extension modules, take a look at Weave.
Re:Downloaded and loved (Score:2)
Bridging between languages with totally different type systems is usually tedious. Try SWIG, or PyRex, or Boost Python.
Specifically, you can't compile python - and interpreted it's just too slow for anything computationally expensive.
Are you trolling or just ignorant? Sorry for being harsh but this statement is wrong, misleading, and overly broad all at the same time.
First, Python is NOT interpreted (y
Re:Downloaded and loved (Score:3, Interesting)
I started with SWIG, and eventually decided it was easier to just write my one function myself instead of trying to learn all the ins and outs of swig. I didn't discover pyrex 'til later, and haven't really looked into boost.
compiled to byte code and then executed in a VM
Then I'd prefer that it not require a VM.
If you think it's to slow because it's not native the same goes for Java and C#.
Correct.
to point out that saying "it's too slow" without qualification is an
I beg to differ with AccordianGuy's assessment (Score:5, Insightful)
Re:I beg to differ with AccordianGuy's assessment (Score:2)
Python, prototyping, and gmailfs (Score:5, Interesting)
Re:Python, prototyping, and gmailfs (Score:2, Funny)
Try it, I just did.... (Score:3, Interesting)
Using Tkinter for a GUI is not as simple as I h
Re:Python, prototyping, and gmailfs (Score:2)
Thoughts of Python... (Score:5, Interesting)
I wasn't a Python Zealot(tm) until I tried it... in fact, just the opposite.
When I heard about the whitespace-is-significant, I had nightmarish flashbacks of MVS JCL (thoughts of which still cause me to twitch uncontrollably). As such, I refused to even look at Python seriously for quite some time.
However, that being said, once I actually did get over my (admitted) prejudice and gave it a serious test - it earned an official "WOW", something which few languages have ever done for me. Never mind that I was as productive while just learning Python as I am as an expert in any of the other languages I use regularly.
Now, I'm an official convert. Python gives you all the tools you need, but never forces you to use the wrong one for the job.
All I need to do now is find a shop that actually uses Python...
Re:Thoughts of Python... (Score:2)
Interesting to hear this, because that is exactly my reaction to python.
"Wow, sounds interesting but when you cut and paste chunks of don't you run the risk of shooting a hole in your foot and then somehow choking to death on the fountain of blood?"
I'd be interested to know whether you still dislike the significant whitespace, or have somehow come to like it. And if so, why?
Re:Thoughts of Python... (Score:3, Informative)
Re:Thoughts of Python... (Score:4, Informative)
Get a smart text editor; one that can handle this. When I cut'n'paste Java code in Eclipse, for example, it makes all of thew whitespace perfect. Indenting and outdenting code should be no more than a few keystrokes. ("<<" or ">>" in vim's visual mode. ctrl-[ or ctrl-] in Eclipse. etc.)
This is something I always did in other languages anyway, so Python's whitespace handling never bothered me. Improper whitespace drives me nuts (too hard to read), so a language that enforces proper whitespace is perfect to me.
Re:Thoughts of Python... (Score:4, Interesting)
I tend to use emacs, which can handle indenting in any of twenty different ways, but anyway...
My conceptual problem is that when I cut and paste a block of code to a new place, there is no acceptible default indent level - I might want to end the previous block and start a new one, or I might want to stick this under the if, or maybe it should go outside it, and there's no way for the editor to automatically know and do the right thing. I often in emacs select the whole file and tell it to correct the identation... which is impossible in python?
Re:Thoughts of Python... (Score:3, Informative)
Paste or select a block, C-> indents, C- outdents
Don't bother selecting your whole file & re-indenting the whole thing.
Note that with a brace/delimiter oriented language, you often have to manually insert/delete delimiters...
C-M-\ (indent-region) still works to adjust indent levels (i.e., if somebody indented blocks w/ 2 spaces and your setup is 4 spaces), but it won't move code between blocks.
Entering new code in python-mode is
Re:Thoughts of Python... (Score:2)
Huh. Interesting to know. It's one of those things that seems very scary, and all the various posts about how you can use various indent commands are like saying that you can always move your foot when you point the gun at the ground, not actually helpful. It's good to here from someone who had The Whitespace Fear and now just doesn't care.
Python will have to go next on the list.
Re:Thoughts of Python... (Score:5, Interesting)
I rewrote our Windows-based management tools into Python for myself. Using that protocol library, I've sent quick and dirty py2exe wxWindows programs to customers. "Just unzip and run." Unless they look closely, I'm sure they don't know (and don't care) they're running Python apps.
It's not exactly "in your face" like Zope but it glues together my day.
Re:Thoughts of Python... (Score:2)
Re:Thoughts of Python... (Score:2)
The problem with pythons whitespace is that it causes quite a bit more problems than it solves in my view. Especially when one refactors function and classes (make a local function a global or visa verse) it is just way to easy to break the code, since once you have broken the indention you have broken the programm and its
Re:Thoughts of Python... (Score:3, Interesting)
When you are maintaining code that you didn't write on a version control system, you almost certainly shouldn't be changing code just to reformat it. It causes diffs that are unrelated to meaningful changes in
Re:Thoughts of Python... (Score:2)
Then you need to look at RPG.
The more things change, the more they stay the same:)
Enjoy,
Re:Thoughts of Python... (Score:2, Informative)
Google, ILM, and NASA all use Python. See the Python Quotes [python.org] page.
Re:Thoughts of Python... (Score:3, Informative)
I don't think that data hiding is all that important for OO, after all it doesn't add any functionality, it just restricts access a little bit and is in languages like C++ even easily workarounded via raw pointers or even more evil '#define private public' hacks. Worse of all, data hiding can make it actually impossible or very ugly to workaround bugs in a library.
Anyway, as far as I know Python does
Re:Thoughts of Python... (Score:3, Informative)
There are a variety of
python's list processing rules (Score:5, Informative)
e.g, look at this super-terse, but still legible, sub-array code:List comprehensions are another great feature:This is so amazingly compact when compared with list processing in Java or C++.
Anyhow, hats off to Guido Van Rossum for such a great language. I'll have to check this book out... I've been using the python cookbook (OReilly) and the documentation on the site almost exclusively...
Re:python's list processing rules (Score:2, Interesting)
With Python: [ x ** 2 for x in xrange(100000) if x % 2 == 0 ] (8 seconds)
With Ruby: (1..100_000).select { |x| x % 2 == 0 }.map { |x| x ** 2 } (2 seconds)
but Ruby is supposed to be 10 times slower (not compiled, bigger...) What's happening? (it's not a troll, it's a real question)
Re:python's list processing rules (Score:4, Informative)
Apparently, there is something quite different about ruby's handling of long integers (>32) bits from python's. In the python case, this expression automatically switches to infinite-precision integers (at least for python 2.3). I don't use ruby, so I don't know what it is producing when the numbers get beyond 32 bits. Does it automatically go to long integers?
Anyway, the speed difference in this pair of examples seems contrived to get ruby to do something much faster than python, since it requires 'special' values including integer overflow to exercise this effect. Maybe ruby really has better long integer handling than python. Can any on who knows ruby comment on the result of the overflow?
Re:python's list processing rules (Score:3, Insightful)
With Python: (8 seconds) With Ruby: (2 seconds) With Perl: (<= 1 second)
Re:python's list processing rules (Score:3, Interesting)
On my system (using 1,000,000), Python takes 10 seconds, Perl takes 3. Even using @a=map { $_ ** 2 } grep { $_ % 2 == 0 } (1..1_000_000), forcing Perl to compute the list, Perl finishes in a mere 3-4 seconds. I ran these informal benchmar
Re:python's list processing rules (Score:2, Interesting)
a = [ x ** 2 for x in xrange(1000000) if x % 2 == 0 ]
to
a = [ long(x) ** 2 for x in xrange(1000000) if x % 2 == 0 ]
using time, I get:
[real: 0m21.790s; user: 0m20.290s; sys: 0m0.110s] for the first one, and [real: 0m3.637s; user: 0m3.310s; sys: 0m0.070s] for the sec
Re:python's list processing rules (Score:2)
Personally I'm a fan of (mapcar (lambda (x) ...))
Re:python's list processing rules (Score:2, Flamebait)
Re:python's list processing rules (Score:3, Interesting)
Granted. But
...isn't horrible. And in Lisp:
...is pretty good.
Where the hell did Pythoners (and others) start using the incomprehensible term "list comprehensions"? Isn't the correct term ("function mapping" -- from Lisp, Scheme, Prolog, Mathematica, etc.) still sufficient?
BTW, here's some simple code for doing mapping in Java. Yes, it can be mo
good and bad (Score:5, Interesting)
It is in many ways an excellent book, but geared towards more experienced programmers than I. The style is readable, but the program illustrating introspection (chapter 4 I believe) is really hard to get into. Mark could have chosen a better example.
I particularly liked the way that Pilgrim annotated the code. He started out a chapter with the raw code, broke them into blocks with annotations and then concluded the chapter with a review.
The approach of these diveinto books is to introduce unfamiliar concepts and then dissect them one by one. My only complaint is that sometimes he introduces a lot of things all at once. It would have been better (though less succinct) to use more examples with fewer concepts thrown together all at once. On the other hand, I can appreciate the succinctness of the example programs by presenting them without first dumbing them down. The good thing about diveintopython is that it helped me to read a program pretty easily --although that doesn't imply that I can apply this knowledge..Give me another week or two:) The key question is at what point do I feel like coding on my own? I tried the examples in chapters 1 and 2, and then didn't feel like I could start coding until I finished the first 8 chapters. (and am slowly getting the hang of it).
Interestingly, when I started out, I found that I was referring to Oreilly's Python in a Nutshell [amazon.com] more and more. Didn't look that user friendly at first, now seemingly more useful.
My sense is that programming is a matter of incremental mastery. (First read Fun with Dick and Jane, then read Wizard of Oz, then Melville, then Shakespearean sonnets). This book starts out by throwing out the Shakespearean sonnets at us and then explaining piece by piece until we have a sense of the whole.
Guido von Rossum's tutorial is more of a stepping stone approach, though the example code is more academic than practical.
One advantage of the online book: great hyperlinked references to Rossum's tutorial and other sources.
Despite my griping, this was still a good instructive read (though challenging). And way to go Mark for putting this online for free!
It's also in Debian. (Score:5, Informative)
--Jon
We need a Dive into Zope book (Score:2, Interesting)
The thinner, the better (Score:5, Interesting)
When I see a slender volume sitting among the telephone-directory-sized tomes, I usually pick it up on the assumption that it should be good if it's so lean. I am not often disappointed.
(I just realized that LISP books *all* tend to be rather slender. McCarthy, Siklossy, and Steele all managed to say quite a lot in very little space. Hmmm.)
Re:The thinner, the better (Score:5, Funny)
It's because the chapters are recursive.
Re:The thinner, the better (Score:3, Interesting)
Re:The thinner, the better (Score:2)
(Insert joke about parentheses (()) (here))
I suspect that the Lisp books are so small because the number of concepts in Lisp is rather small. It's just that each concept in Lisp goes a long way.
Re:The thinner, the better (Score:2)
I did a lot of Cobol when I started out ( I am old) and I had this 600+ page Cobol book but I never went past page 18 and it was well worn out all the way to page 18. What was on page 18? First example of more-or-less complex complete program.
Python (Score:4, Insightful)
So I'd heard about Python and that it was good, so (since I like the process of learning new languages) I decided to try rewriting the scripts in python. In about two days I had them doing everything the perl had done and the added functionality as well and with remarkably few bugs.
Eventually I went back to add on more functionality and "Lo!" I had no trouble reading my Python code and even better adding in the new stuff was simple.
The biggest problem with Python has been the lack of a good book, I'll be considering "Dive into Python" carefully - being in the education biz I'm looking for a really good Python book for students.
Why Are These People So Naive? (Score:3, Insightful)
Geez, how did some people become so naive? Just figuring out that professional authors write for money? And you're offended by it?
Re:Why Are These People So Naive? (Score:2)
Why are they a problem? Is someone forcing you to buy them?
It's my impression that authors sign contracts with publishers that set the price, rather than some open-ended deal that sees a publisher agree to pay a fixed price per page. (What's a "page", anyway?) A publisher could not control its costs if it allowed writers to determine what it paid for manuscripts.
Frankly, it's my impression that all those huge books exis
I had no idea (Score:3, Interesting)
Small world.
Re:I had no idea (Score:2)
mirror (Score:4, Informative)
The actual dialogue... (Score:5, Funny)
"...a dialog between him and his manager after showing him a rough 20-page draft:
Manager: "This is really good. You could probably make some money off this someday --
but you did it while employed by us, so now it belongs to us.
Cough up the rest.
You have a month."
http://yro.slashdot.org/article.pl?sid=04/08/03
Torrent for book? (Score:2)
Also in the ActivePython docs (Score:5, Informative)
Practical Common Lisp (Score:5, Interesting)
Learn CL while writing a flexible MP3 database, a spam filter or a generic parser generator for binary files. How about a streaming MP3 server or a unit test framework? It's all in there without the boring stuff, which usually accompanies books like these.
Re:Practical Common Lisp (Score:2, Insightful)
Actually, instead of being stupid like you suggest, the free implementations are moving towards broad compatibility with each other instead.
It is dumb to insist there only be one Lisp implementation because there are different trade-offs to be made in terms of CPU, memory, convenience, etc. The point of the ANSI standard is to m
Re:Practical Common Lisp (Score:2, Insightful)
Completely Slashdotted!! (Score:3, Informative)
Dive Into Python Table Of Contents [64.233.167.104]
mod_python/PSP (Score:5, Interesting)
Which now comes with PSP. That is, server side web scripting using
Python as the language. Similar in spirit to PHP, just using Python.
Amazingly much more fun than PHP.
Making money from technical books - not happening (Score:3, Interesting)
Reading them, one gets the feeling that its primary purpose is to allow the author to make some payments on a car or mortgage.
Unless we are talking about a book that really interests a LARGE portion of the geeks out there, the above statement is really missing the point. I don't know any technical book authors who do it for the money. I am certainly not writing for the money. Royalties are nice, but they are really small in the end, especially when you consider the time and effort that you put in writing technical books. In addition, think about the 'life expectancy' of a book that covers a technical topic - not much longer than firefly's.
Long story short, one doesn't write this type of stuff to make money, and Mark certainly didn't write Dive into Python for $$$ - I've had it bookmark in my Simpy account (URL in sig) for 6+ months now. I just wanted to get this straight, so there is no confusion. This may also be interesting to those considering writing a book on a technical topic.
With so many links in one article... (Score:2, Informative)
/.'ed but mirrored (sort of) (Score:3, Informative)
Re:What for almost absolute beginner? (Score:2)