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Data Munging with Perl
The Scoop Larry Wall, so goes the story, needed to glue together two systems on opposite sides of the country. Calling on the virtues of Laziness (why throw together something for just one job) and Hubris (why not write a new language?), he created Perl. Though it's found new niches in the post-web world, Perl earns its bread and butter munging data.
Dave Cross has put together a friendly and handy compendium of techniques, tricks, and best practices. Suitable for raw novices to experienced intermediates, Data Munging with Perl is a gentle but firm romp from flat text, past structured and binary files, to the realm of custom parsers. Clean examples and lots of modules accompany the explanations.
What's to Like? The book plots a natural course through topics ordered by complexity. It opens with a theoretical overview of data processing. This introduces terminology and outlines the general types of data one might encounger. Additionally, the author writes with the authority of experience when exploring the basic approaches and best practices. While other books aimed at novice users shy away from programs-as-filters and data structures, Cross prefers to instill good habits from the start.Beyond munging data, the book provides a decent introduction to idiomatic and effective Perl programming. While the brief tutorial won't magically produce new JAPHs, the thoughtful and continual devotion to good technique and skill will inspire smarter programmers. More important than knowing many useful tricks is knowing when and how to use a handful of tools -- and where to go for more.
The overall level of quality is excellent. The binary data chapter stands out as the clearest explanation available, and the information on munging dates and times will save readers plenty of grief. Additionally, the entire parsing section introduces a handful of powerful but sorely-underused tools to handle HTML, XML, and even creating custom parsers. Rounding out the curriculum is an appendix that explores the larger modules, mentioned earlier, in more detail (XML::Parser, DBI, Date::Manip).
What's to Consider? Only two things might turn readers from this book. The first is its deceptive length. While the text is short, the examples are clear and the text packs a lot of wallop in what's there. Careful readers who follow the links to other resources will have little trouble supplementing their education. (On the other hand, another ten pages describing Parse::RecDescent would have been a nice addition. It's hard to fault the author for deferring to the module's voluminous documentation.)Second, longtime Perl programmers may find little new material, particularly if they are familiar with the wealth of modules on the CPAN. The intended audience is clearly new and underexperienced programmers. While there's plenty of good advice presented well, the book falls more toward the tutorial side of the aisle than the reference section. This does not detract from the book, but it does narrow the base of potential readers slightly.
The SummaryManning Publications continues its fine line of Perl books with the consistent and powerful Data Munging with Perl. Coders looking to transform data somehow and hackers who want to take advantage of Perl's unique features will improve their knowledge and understanding. If you find yourself working with files or records in Perl, this book will save you time and trouble. Table of Contents- Introduction
- Data, data munging, and Perl
- General practices to use when munging data
- Generally useful Perl idioms
- Pattern matching
- Data Munging
- Unstructured data
- Record-oriented data
- Fixed-width & binary data
- Simple Data Parsing
- More complex data formats
- HTML
- XML
- Building your own parsers
- Conclusion
- Looking back -- and ahead
- Modules reference
- Essential Perl
You can purchase this book at ThinkGeek.
Get a second monitor to read documentation from. Not only would it pay for itself within 4 books, but it's more useful than a stack of spent books.
--
Log files are generally fairly structured data.
CSV files are structured data.
Free flowing ASCII text is unstructured data. :).
Shakespeare's sonnets, however well formed, are unstructured data
(unless you can come up with a parser that recognizes iambic pentameter...
Falling somewhere in the middle is binary data. It has a structured format but freeform contents. Consider the various sound, image, and video formats. Maybe Shakespeare's sonnets could fall into this category too... :)
There are situations where you could want to analyze each form. Parsing Apache log files is a slightly different task than analysing formal XML documents or sloppy HTML pages or messy ASCII email. This book helps give you a feel for which situation you may be dealing with, and thus what tools & techniques might be useful for that situation.
Though some will tell you otherwise, this book has nothing to do with "Buffy the Vampire Slayer." Sorry, grep.
DO NOT LEAVE IT IS NOT REAL
Next year I'll be writing a book about Parse::RecDescent (or its successor Parse::FastDescent) and grammatical parsing techniques.
Damian
Perhaps I'm still stuck in the paper age (somewhere between bronze & silicon), but I find myself spending $50 a pop for progamming books I only skim through. If I need reference material, I hit PHP.net (for my PHP projects).
Am I missing something?
Dude, take your medication before you post. This book isn't going to tell the bad guys how to get your credit card number from the porn site you just visited. The bad guys already know how to get every piece of data about you that they want. So go back to your room in your mom's basement and put the aluminum foil hat back on your head. Remember - shiny side out.