Mastering Regular Expressions, Second Edition [Paperback]

Jeffrey E.F. Friedl (Author)

Editorial Reviews

Amazon.com Review

Regular expressions are a central element of UNIX utilities like egrep and programming languages such as Perl. But whether you're a UNIX user or not, you can benefit from a better understanding of regular expressions since they work with applications ranging from validating data-entry fields to manipulating information in multimegabyte text files. Mastering Regular Expressions quickly covers the basics of regular-expression syntax, then delves into the mechanics of expression-processing, common pitfalls, performance issues, and implementation-specific differences. Written in an engaging style and sprinkled with solutions to complex real-world problems, Mastering Regular Expressions offers a wealth information that you can put to immediate use. --This text refers to an alternate Paperback edition.

Review

"Indispensable for text processing wizards and regex newcomers alike." - Paul Hudson, Linux Format, February 2007 "In addition to the sheer volume of information, one thing that sets this book apart is that the author uses "real-world" rather than contrived examples. A few of the examples were situations that I have yet to come across, but many were either "been there, done that" or things that I had to go out and try." - James Mohr, Linux Magazine, April 2007 --This text refers to an alternate Paperback edition.

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Product Details

• Paperback: 496 pages
• Publisher: O'Reilly Media; 2 edition (July 15, 2002)
• Language: English
• ISBN-10: 0596002890
• ISBN-13: 978-0596002893
• Product Dimensions: 9.2 x 7 x 1.2 inches
• Shipping Weight: 1.7 pounds
• Average Customer Review: 4.5 out of 5 stars  See all reviews (137 customer reviews)
• Amazon Bestsellers Rank: #503,443 in Books (See Top 100 in Books)

Customer Reviews

Most Helpful Customer Reviews

109 of 117 people found the following review helpful:

5.0 out of 5 stars I need more stars... Bravo Jeffrey, December 8, 2001

By	"sherzodr" - See all my reviews

This review is from: Mastering Regular Expressions (Paperback)

Jeffrey Friedl's "Matering Regular Expressions" does a facinating job in taking you through the jungle (and I mean jungle) of RegExp.

I am a Perl/CGI programmer, and I had considered myself good at RegExp even before I read this book. Most of the things I knew were from Programming Perl, 3rd edition (chapter 5, Pattern Matching). But I still decided to give Jeffrey a chance since I was having some trouble with my Parse::Syntax module, which is designed to parsing *any* programming language and highlighting the syntax accordingly (provided it has a syntax/grammer file written for the specific language). The accuracy of the parser (and more importantly the speed) does depend on well crafted regular expressions.

As I started reading the book, I couldn't stop. I took it to my school's cafeteria with me and no one could make me leave untill I finished the whole book. I was excited. I was pleased! Here is the outline of tha chapters:

Chapter 1 and 2 introduce you to regular expressions and give some basic regex examples. Mail utility and date matching is two of them.

Chapter 3 mostly talks about conventions that all the regex tools follow and their differences.

Chapter 4 deals with Traditional NFA, POSIX NFA and DFA regex engines and their pros and cons. What you'll like the most is the details provided by the author on each and every single example. He also uses a lot of step-by-step illustrations to take you deeper into the regex engine itself and see/feel how it works. He shows the point of backtrackings and provides awesome benchmarks. He uses such examples of matching a quote, allowing escaped quotes inside the pattern, matching C-style comments, IP addresses and many more.

Chapter 5 deals with writing efficient regular expressions for NFA engines. It also re-vists some of the examples provided in the previous chapter and fine-tunes them.

Chapter 6 and 7 deals with Tool-Language specific features of Regex engines. Chapter 6 is dedicated to Awk, Tcl and GNU Emacs, whereas chapter 7 is entirely dedicated to Perl, good over 100 pages of Perlism.

It's true that there're features that Perl 5.6 offers when it comes to regex that didn't exist at the time this book went to press, (lookbehinds, for example). But this no way makes this book dated. Just take my word for it. Jeffrey put together a great masterpiece that will not die for many years, no matter how fast the technology tends to enhance
Haven't read anything more exciting than this for many years.

34 of 34 people found the following review helpful:

5.0 out of 5 stars Those wise birds!, May 3, 2001

By	Alfred Anzlovar - See all my reviews

This review is from: Mastering Regular Expressions (Paperback)

I got Mastering Regular Expressions in 1998 and I peek back regularly and it am proud to say is one of most used and useful books I own.

Regular expressions are for everyone. They are simple to write and can be close to impossible to read and even unimaginably harder to understand. But reading comes after you can craft one.

And this art of crafting RE is explained in astonishing detail and analysis in this book. Reader is carefully guided through basics, differences and common and uncommon pitfalls. Some of the parts are definitely not for the faint hearted! And this is especially true for parts that cover Perl RE. While main topic is Perl RE engine, a deep-enough travel through different RE dialects is made to help RE-crafting in almost any tool that supports REs.

I've used the methods described in the book in tools as different as MS VC++, various editors, search engines and programming (Perl, PHP, C++, ...). The ability to use RE usually impressed people to the point they were sure I am using some incredible magic.

But I must say that the most useful feature delivered in this book was ability to PARSE, UNDERSTAND and FIX a (slow, broken, strange acting) RE. This can be slowly absorbed by reader's (open) mind while carefully reading the book. The difference between meant/written can be as extreme as it can get in RE. I can (proudly) say I've been able to fix several complex REs, by simply (one could say blindly) following the rules laid in the book.

My opinion is thath without this book real understanding of RE is almost impossible. I recommended it all of those who use programs that support (any form) of RE engine. It will help them solve some (hard) problems incredibly fast!

33 of 36 people found the following review helpful:

5.0 out of 5 stars Simply Outstanding, September 26, 2002

By	Fruitcake - See all my reviews

This review is from: Mastering Regular Expressions, Second Edition (Paperback)

I bought this book on a whim, mainly because I try to buy (and read... ugh!) a hard-core technical book every month or so, but mainly because my UNIX scripting abilities have become rusty with disuse. I used to be able to write a tight, 10-line csh script to mangledit thousands of files at a single time. Now I hack away at files manually with vi. The other day, I even forgot how to search & replace. My kung fu isn't nearly what it used to be.

It usually takes me about a month to slog through a new book (especially academic texts, which are great but make you want to have a stiff martini before each new chapter) but I tore through Friedl's book in a few days. It's an outstanding reference for understanding & learning to use regular expressions.

Regexes can be cryptic to say the least, but Friedl offers many examples, broken down into step-by-step instructions and explanations of how each regex works (in many cases, right down to the individual character level). He covers a variety of platforms and languages - the hardcore Perl enthusiast will enjoy this book greatly, but he offers fairly equal time to alternative languages like Java and the "grep" family.

All that said, this book is an outstanding technical reference, pure and simple, for two reasons:

- Friedl uses an interesting new typesetting convention to illustrate which sections of text are regular expressions, and which sections are not. It's hard to describe (and impossible to reproduce here) but they look like 90-degree braces at the upper-left and lower-right corners. This is a FANTASTIC approach and I for one would love to see this extended to other technical books.

- Speaking of other things I would love to see extended to other technical books, THIS BOOK HAS ALMOST NO ERRORS! This is even more impressive considering the fact that, with regular expressions, screwing up EVEN A SINGLE CHARACTER is significant. Nothing [upsets]memore than spending $50-100 perfectly good dollars on a sloppy, error-laden, grammatically-challenged, poorly-edited, ill-reviewed and badly-structured book (which pretty much describes 90% of all the technical books out there). He made a few mistakes, the vast majority of which are extremely trivial in nature, and all of which were quickly posted to his website as errata. If only the other 90% of the technical authors out there were even half as diligent.

All told, this book belongs on your bookshelf.