How deep down the rabbit hole do you really NEED to go? I had a serious need to get on top of regular expressions to solve one particular problem. I looked at several online tutorials which didn't take me where I needed to go, so I ordered Mastering Regular Expressions after reading the Amazon reviews. I always look at the negative reviews first. In spite of the negative reviews I ordered the book with an open mind.
When the book arrived I began reading it with enthusiasm. In the preface there is a small section on "How to Read This Book". I bought into the author's suggestion to read the book's first six chapters first. I was captivated through the first three chapters, and then somewhere in chapter 4 I began to get very weary with information overload. After putting the book down for a couple of days I decided to skip the rest and use what I needed to write the one regular expression I had need of. The book did successfully help me accomplish this, so I gave it 3 stars. Not only did it give me the information I needed that the online tutorials didn't, it also gave me the confidence I needed. For that, which I am grateful, I would have liked to have given it more stars. I think many of those in need of learning about regular expression could be well served by a "lite-edition" of this book. Perhaps someday when I have the time and the need I may try to wade through the rest of the book, but as it is now Mastering Regular Expressions took me far farther down the rabbit hole than I really needed or wanted to go.
If you need to get on top of Regular Expressions, I would recommend this book, however just be ready to be taken far deeper than the average coder probably needs to go.

An incredible book. Absolutely incredible. It will take 200 lines of your code and reduce it to 1 or 2 lines. It will open your mind to search and replace possibilities. Your life will change (just kidding). It's a great deep book.

However, I agree with the comment that one should not begin learning regex with this book. it's a little too advanced. Go on the internet, get an introduction. Or else, buy one of the introductory books on the subject first. But definitely get around to buying this book!

This book is seriously worth the money. I knew just enough regular expressions to get by, then I started reading this book and it has paid off already; saving me time on several long, arduous tasks.

The book is really well written, very interactive w/ quick, quizzing questions mixed throughout the chapters. The authors writing style is very effective and surprisingly entertaining.

If you don't know much about regular expressions or even if you think you do, purchase this book. It will be well worth it.

I have been in computer software developer over 7 years now and never really used regular expression until a year ago. True, you can live without it. But, with regular expression at hand, you climb up another level of programming. Code will be much concise and code research will be like a breeze.

Anyway, I didn't read this book entirely since later chapters explain intricacies and subtle differences of each specific language, e.g., java, perl, php, etc. It didn't take long to apply the knowledge I gained to real work and benefit. By the time I completed the first chapter, I already started to get rewards. My life is a lot easier now.

Even with only the first 3 chapters, this book is well worth its price. The author did superb job explaining what's going on behind the scene and guide you through the right way of constructing regular expressions for various situations. Of course, he will show you common pitfalls to avoid, too. Very detailed and comprehensive.

Highly recommended.

Before reading this book, I would have considered myself an intermediate regexer. After the first 2 chapters, I realized how novice I really was. Having only made it through 5 chapters of this book, I can't say enough about it. The detail and step-by-step analysis that Mr. Friedl takes to describe the regex matching process is the best I've ever seen. It's little things that make the analysis easy to follow -- like the brackets he uses to mark the regex, and the small triangle cursor to show where the engine is in the matching process. I continue to look forward to each new chapter. Thank you for a wonderful work of art.

Are you a programmer working on text-related tasks? If you are, then this book is for you. Author Jeffrey Friedl, has done an outstanding job of writing a cool book that will interest anyone who has an opportunity to use regular expressions.

Friedl, begin with an introduction to the concept of regular expressions. Then, the author takes a look at text processing with regular expressions. Next, the author provides an overview of features and utilities, plus a bit of history. He also explains the details of how regular expressions work. The author continues by working through regular expressions examples. Then, he discusses efficiency in detail. Next, the author covers Perl regular expressions in detail. He then looks at Sun's java.util.regex package. The author continues by looking at .NET's language-neutral regular-expression package. Finally, the author looks at PHP's preg suite of regex functions.

This most excellent book should expand your understanding, even if you consider yourself an accomplished regular-expression expert. Perhaps more importantly, the book concentrates on mastering a particular implementation!

Many people only barely utilize regular experssions, having been unable to get more than basic expressions to work. There are a lot of reasons for this - shell escapes, man pages that are terse to the point of being cryptic, etc. This book is a clear and very readable trip through practical regular expression creation and application that will enable the reader to get the most out of grep, awk, perl and other programs that use regular expressions.

Jeffrey Friedl describes regular expressions at an amazing depth and precision. Regular expressions are not easy and the quirks of the different tools (including their exact version and for what operating system) make writing them to an irritating black art. A black art to almost anybody. MRE sorts everything out in a comprehensible fashion. The price the reader has to pay: a very dense book, a need to follow the details until your head starts swimming and a lot of strain on the memory about what works, how and where.


MRE is somewhat easier to comprehend for a reader with a strong Pearl background. Also a good prior understanding to regular expressions is a true asset here. If you have neither, you do not need to despair. Jeffrey Friedl explains everything thoroughly from the ground up.


The writing style is very pedagogical. Important things get repeated quite often. Still this book is very dense. The flow is dry: no rhythm, special sense of humor or wit sweetens your wading through the material. Nevertheless Jeffrey Friedl kept my interest through the pages though the reading felt like hard work.

I do recommend this book to the truly dedicated reader.

This is must-have if you are trying to learn regexps or improve your knowledge of them. It carefully walks you through how to construct expressions, covering everything from the most basic tasks to complicated scenarios. It explains how matching works, so you can really understand what is going on behind the scenes.

What more can I say besides what everyone else has said.
This is a WONDERFUL and POWERFUL book on Regular Expressions.

From just-beyond-beginner to advanced, this book provides a fantastic view into the world of Regular Expressions and the practical thinking involved with them. However, without at least a semi-understanding of the concepts you will not be able to get through the book very quickly.

I walked away with MUCH more knowledge than I had expected to. This applies to not only regular expressions, but also to rational thinking/planning when it comes to data and programmatic analysis.

This is a great book for learning about regular expressions. It goes into much detail, yet still remains an easy read for a novice who has not had much experience to RegEx. Recommended.

Regular Expressions need to be fully mastered in order to truly gain access to the power of many languages and programs. Whether you are working with Perl, PHP, Java, .NET, Ruby, C, Python or any of a variety of other languages the use of regular expressions allows you to work with your data in powerful ways. As a general rule most books that even mention regular expressions just mention a very few of the common ways to build an expression. This book takes the reader well beyond that level and explores the many more unusual ways regular expressions can be used. If you don't know what a regular expression is then you have no need for this book, but if you have ever worked with regular expressions then you are in for a treat with this book. I have used them for years and built a whole spam filter system around regular expressions but there is so much more they can do and this book can make you an expert.

After a basic introduction covering the most common tasks regular expressions are used for (substitution, selection, wild cards, etc.) the author delves into examples of regular expressions in Perl, and follows that with a section discussing some of the variations in regular expressions as implemented in different languages and common programs. One of the most important features of the book is the plethora of real world programming examples. Mastering Regular Expressions is highly recommended to anyone who wants to completely master the full art of regular expressions.

Regular expressions are not really for the person playing at would-be programmer. It is to the text processing person what a top-of-the-line drill is to a carpenter. It requires a dedication to detail, an ability to write out exactly what needs to be done and why it works. Regexs are used in a context. Perl for example, helps the process along by supplying a well-packaged and documented environment for regex. But this means you have to learn Perl, or Java, or PHP, Python, Ruby, whatever. This book is for the kind of person that fits somewhere in the above described mix. It is however, THE book to have when you do care enough. It is not an easy book for a beginner or those in a hurry. Whatever it is that is covered here is done well and authoritatively (spelling ?). The author knows his stuff and the pains-taking effort he talks about in his Preface is obvious to the student of the book.
I believe this topic lends itself to being best taught by looking hard at a big bunch of non-trivial examples, with a lot of surrounding comments. They are in the book, I wish there were more. Perhaps the buyers of this book, along with the regex gurus out there could start posting well-crafted regexs to some well-known spot. I believe that O'Reiily, the publisher of this boo already might have such a posting site.
Kudos to O'Reilly and to the author for a wonderful contribution to the computer programmer/science community

Regular Expressions can be confusing unless you use them everyday. This book is a great quick reference and will provide the deeper level information you need for those harder solution.

For many savvy computer users, regular expressions embody the perfect utility: a well defined, documented, and designed tool that makes complicated and arduous jobs short and easy. That being said, the craft of regular expressions (hereafter, `regex') makes about as much sense as a foreign language to the uninitiated or novice. Regex have no immediately apparent meaning to those unfamiliar with them, and are so enigmatic in appearance that many users do not even attempt to understand them - writing them off as a tool only for experts. "Mastering Regular Expressions" sets out to not only make regex understandable, but easy to apply to a wide range of situations.

Stylistically and structurally, this is one of the most unique O'Reilly publications I have read. The author even says in the early chapters to think of the book as a novel, and not as a reference (the book's structure doesn't really lend itself to being a reference book anyways). The mindset that the author applies to his writing makes a discernable difference in how the book reads, and it feels more like a chronological story and less like a textbook as a result. Even the quizzes that the author scatters throughout the book are treated as part of the "story", and the solutions are on the very next page rather than in the back of the book or at the end of the chapter. As a result, the book is very easy to read, and flows extremely well. It feels much less like a textbook and more like a narrated lesson from an enjoyable professor.

With a topic as muddy and potentially confusing as regex, I was worried that the text would be just as confusing to follow. However, I was pleasantly surprised. The text itself is very well written, and very clear. There was never an instance in which I had trouble comprehending what the author was trying to communicate, and I almost never had to go back and re-read something multiple times to grasp the concept.

Furthermore, the text is full of excellent examples with accompanying explanations. The author almost exclusively teaches through example, and as a result, most of the lessons are extremely practical and great real-world applications. All of the code examples (of which there are many page-long instances of) are very well documented, and easy to understand.

Regex really is one of the most portable utilities that exists in the UNIX world. It can be applied to an enormous number of situations, and is interoperable with a laundry list of other tools and languages. As such, regex is not only a tool, but a general concept that must be grasped prior to proper usage - and this is what the first several chapters focus on. Thinking about problems in terms of regex is something that takes practice, and does not come easily to most people. This book tends to teach through example, and jumps right into matching simple regex to text lines to demonstrate how regex works. This brings me to my next point.

This book is not for beginners. I cannot stress this enough. The chapters not specifically aimed at a language require solid knowledge of a structured language like C++ or Java. Granted, the book really won't appeal to anyone that doesn't use computers on an advanced level on a regular basis; however, what I want to stress is that regardless of the reader's level of computer experience, if the reader does not have advanced knowledge of text handling in serious computer languages, most of the book's content will be too complex.

On the same note, and this is not a bad thing, about half the book is language-specific. There is a chapter for Perl, PHP, and Java. Obviously, if you don't know these languages, then most of the content of these chapters will be useless. This is not to say that the book will be useless to you if you don't know these languages - the non-language specific chapters occupy a large portion of the book, and contain more than enough material to master regex - however, the reader should be aware that just under half the book is aimed at specific languages.

Overall, this book is nothing short of fantastic. The audience for it is very limited - however, the author manages to make a concept difficult to understand, and even harder to master, easy to read about and learn. Clearly, a lot of thought went into the craft and design of this book, and it shows. I would highly recommend this book to any programmer, system administrator, or computer power user.

Very nice, good explanations.
Not exactly a plain old reference type book.

Incredibly well written and thought out, Mastering Regular Expressions explains both the syntax and philosophy behind regular expressions. You'll find that it is throughly researched, every nuance of a given regex implementation of the four featured languages (Perl, Java, ASP and PHP) is covered in extraordinary detail, containing information available NO WHERE online.

I bought this book after tooling around with regular expressions for a year or so and having limited success, my training having been limited to short online tutorials. After reading Friedl's guide, I have become much better at CORRECTLY programming regular expressions and "thinking regular expressions", that is, changing my outlook on a given task in order to apply regular expressions. I would highly recommend this book to anyone who deals with textual data on a daily basis, including, programmers, web developers and writers of any type.

I don't know about you, but in over 20 years of Unix use and work, I've always had a "problem" with regex. Yes, regular expressions are ANYTHING but "regular!" ...except that the notion extends to parsing text for patterns that are common.

Using regular expressions has always been a hurdle for me. I mean, you HAVE to be able to manage them at least a little in order to be proficient with Unix, but Mastering them, that's another story entirely. Jeff's (if I may call him Jeff) book is stellar. It reads easily and provides meaningful topics on using regex to your advantage.

I can't say enough about how well put-together this book is for the average person. Every topic is clearly visited and the discussion is pleasantly light and, at the same time, technically concise so as to provide real, useful help to using regular expressions. Here is an example:

"Mimicking atomic grouping with positive lookahead"

I consider this book to be a "brain dump" by perhaps the most accomplished regex guy in the industry. In the best of O'Reilly traditions, the book is very well laid out and presented. The quality of editing and "fit-n-finish" of the book are representative of this 3rd Edition.

If you encounter Regular Expressions in your work or as a hobbyist, this book shines a light into the darkness that opens the world of regex to you. It has been very practical and useful for me and it has really helped me be a much better regexer!

Well written, informative, and surprisingly accessible. I have some great new tools to do my work efficiently.

This book is about a very powerful programming tool. Most documentation that mentions regular expressions doesn't even begin to hint at their power, but this book is about mastering regular expressions. Regular expressions are available in many types of tools such as editors, word processors, system tools, and database engines, but their power is most fully exposed when available as part of a programming language. Examples include Java, Visual Basic, Perl, VBScript, JavaScript, sed, and awk. Regular expressions are the very heart of many programs written in some of these languages.

This book will interest anyone who has an opportunity to use regular expressions. If you don't yet understand the power that regular expressions can provide, you should benefit greatly as a whole new world is opened up to you. This book should expand your understanding, even if you consider yourself an accomplished regular expression expert. Programmers working on text-related tasks, such as web programming, will find a gold mine of detail, hints, tips, and understanding that can be put to immediate use. I've not found this level of detail and thoroughness in any other book.

Regular expressions are an idea that is implemented in various ways by various utilities. If you master the general concept of regular expressions, you'll find it easier to use a particular implementation. This book concentrates on that idea, so most of the knowledge presented here transcends the utilities and languages used to present the examples. You'll probably get the most out of this book by reading the first six chapters in sequence. The last four chapters cover regular expression specifics of Perl, Java, .NET, and PHP, and here is where you can skip around based on your need.

Chapter 1, Introduction to Regular Expressions, is geared toward the complete novice. It introduces the concept of regular expressions using the widely available program egrep, and offers the author's perspective on how to think regular expressions, instilling a solid foundation for the advanced concepts presented in later chapters. Even readers with prior experience would do well to skim this first chapter.

Chapter 2, Extended Introductory Examples, looks at real text processing in a programming language that has regular expression support. The additional examples provide a basis for the detailed discussions of later chapters, and show additional important thought processes behind crafting advanced regular expressions. To provide a feel for how to "speak in regular expressions," this chapter takes a problem requiring an advanced solution and shows ways to solve it using two unrelated regular-expression-wielding tools.

Chapter 3, Overview of Regular Expression Features and Flavors, provides an overview of the wide range of regular expressions commonly found in tools today. Due to their turbulent history, current commonly-used regular expression flavors can differ greatly. This chapter also takes a look at a bit of the history and evolution of regular expressions and the programs that use them. The end of this chapter also contains a guide to the advanced chapters. This guide is your road map to getting the most out of the advanced material that follows

Chapter 4, The Mechanics of Expression Processing, ratchets up the pace several notches and begins the central core of this book. It looks at the important inner workings of how regular expression engines really work from a practical point of view. Understanding the details of how regular expressions are handled goes a very long way toward allowing you to master them. The next chapter puts that knowledge to high-level, practical use. Common but complex problems are explored in detail, all with the aim of expanding and deepening your regular expression experience. Chapter 6 looks at the real-life efficiency ramifications of the regular expressions available to most programming languages. This chapter puts information detailed in Chapters 4 and 5 to use for exploiting an engine's strengths and stepping around its weaknesses.

Chapter 7 closely examines regular expressions in Perl, arguably the most popular regular expression-laden programming language in use today. It has only four operators related to regular expressions, but their myriad of options and special situations provides an extremely rich set of programming options and pitfalls. The very richness that allows the programmer to move quickly from concept to program can be a minefield for the uninitiated. This detailed chapter clears a path.

Chapter 8, on regular expressions in Java, looks in detail at the java.util.regex regular expression package, a standard part of the language since Java 1.4. The chapter's primary focus is on Java 1.5, but differences in both Java 1.4.2 and Java 1.6 are noted. Chapter 9 contains the documentation for the .NET regular expression library that Microsoft neglected to provide. This chapter provides the details you need to employ .NET regular-expressions to the fullest regardless of what base language you're working in. Chapter 10 provides a short introduction to the multiple regex engines embedded within PHP, followed by a detailed look at the flavor and API of its regex suite, powered under the hood by the PCRE regex library.

Overall, this is a very complete guide to regular expressions with plenty of examples and I highly recommend it.

If you have ever been frustrated trying to figure out Regular Expressions (RegEx) based only on a table showing symbols and a few paragraphs of explanations obviously written by someone who assumes you are already familiar with the concept, then this book is for you. Don't be daunted by 480+ page size of this title; before you reach the end of chapter 2 you find yourself with a solid understanding of the concepts, structure, syntax and "keywords" in common use by those utilities, programming languages and applications that incorporate RegExs. The middle of the book covers implementation of RegEx in different environments, techniques for creating the expressions, and methods for creating efficient expressions. The end chapters are specific for Perl, Java, VB.NET and PHP users.

The only minor issues I had was in the tools used to demonstrate the concepts. Although no tool used cost the reader money if they wish to hands-on follow along, some of the downloads are from third-party sites which have no guarantee of offering the download by the time you get the book. Additionally, the author makes heavy use of Perl to demonstrate RegEx in scripting, which is fine for Perl users, but those that use other languages to fend for themselves. Seeing additional examples in other free languages, such as VBScript or JScript would have been nice.

Overall, Mastering Regular Expressions is an excellent choice for both learning the basics as well as better preparing yourself to apply them in real-world situations. The writing style is easy to understand and follow, and the layout allows this book to be a learning resource now, and a decent general reference later.

This book is an invaluable resource. I learned more than I wanted to know about regex after reading this book. The authors breaks things down to the smallest detail and discusses each aspect. He covers regular expressions, their engines, their use, and some tips and tricks without losing the reader.

If you are just learning regex, I don't recommend this book - but if you know a little and want to take your regex to the next step, this is the book for you!

I've corresponded personally with Jeffrey Friedl several times over the last few years, and I remember being at once impressed with his attention to detail and his focus. I was invited to be one of the technical review editors for this third edition of his authoritative book on Regular Expressions, but had to pass due to time constraints.

However, I am pleased to state that whoever the tech reviewers were, they did a thorough job on this one from O'Reilly. This book has matured over these three editions to become what I would consider the most detailed and valuable book about Regex on the planet - and that means whatever your favorite programming language or platform is.

You see, Regular Expressions is in itself a language, and transcends programming languages and platforms because the concepts are basically the same across all languages - whether it be Perl, JAVA, C#, Visual Basic, Javascript, PHP, Ruby, Python, TCL - you name it.

And this book focuses on the mastery of regex, not being a reference tool. Though each language has a different syntax for handling objects and methods, the underlying objects and methods are the same with Regex, so even complex examples shown in one language directly translate to the other languages.

Suffice to say that there are basic concept chapters that are really language - agnostic, and then specific sections on PHP, .NET, JAVA, and Perl. The book covers practical Regex techniques and most importantly, it gets you to the conceptual level where you can begin constructing Regex patterns on your own, without having to look for "examples".

For .NET developers, Jeffrey provides a complete table-based overview of .NET's Regular Expression flavor, with a focus on the new features available in .NET 2.0, including class subtraction, RegexOptions, and named capture.

In sum, let me just say that any developer who finds the need to manipulate text - whether it be scraping a web page, creating a report, importing data, or a hundred other applications, is going to need Regular Expressions. Jeffrey's book provides a complete and mature approach that is fresh, timely and detailed. I would recommend this book for any developer.

§
The third edition just came out -- and that makes 10 years since this book was first published. That statistic alone indicates the steady value of "Mastering Regular Expressions" across the constant changes in applied software technology over that time. Regular expressions, still the most under-used power tool, needs a book like this.

Specifically, this third edition features enhanced coverage of PHP in the early tutorial chapters, plus an all new chapter devoted entirely to PHP regular expressions.

Also new in this edition, the Java chapter has been rewritten and expanded to reflect new features as Java itself has developed.
§

Regular Expressions are a powerful pattern matching process built into many programming languages (but often hidden and not fully exploited).

If you are verifying input from a form or analyzing an HTML page or engaged in any other sort of pattern matching, Regular Expressions are something you should master.

The problems addressed by this book are (a) regex is poorly documented in general and (b) it has grown up ad hoc: every language's implementation is different from every other, sometimes very different.

The book does a good job of documentation and explanation in the early chapters. But in the later chapters it falls prey to the problem it is trying to solve. If you use Perl or Java or VB.NET, then this book gives a lot of very important information not easily found elsewhere.

On the other hand, if you use PHP, MySQL or JavaScript (as I do) you have to look elsewhere for the advanced topics.

Get the small pocket reference guide instead of this book! It is difficult to find what you want if you don't know exactly what you are looking for. I admit it covers the subject very well, but if you don't know Regular Expressions thoroughly, you have to read every word of the book or look forever to find what you want. Just buy the pocket reference guide and go to the library once a year when you need this thing.

The only book to explain regular expression in a clear and exhaustive manner, covering differences between the most important programming language in which regex are used.

A "must have".

I have known about regular expressions for a long time, but they have always been some kind of mysterious secret code. Recently I was reading something else that pointed out the power of regular expressions, so I decided it was time to learn regular expressions once and for all. After reviewing the available books on Amazon, I chose this one. I was not disappointed.

After reading just the first few chapters, I have been able to put them to work and make my life a lot easier. As a software engineer, I'm always doing searches through code or search/replace operations. I am now able to do more precise searches and do search/replace operations I never dreamed were possible before.

Learn regular expressions now! Get this book!

Back in 2000 I had to complete some task and another engineer said "Use a Regular Expression". Ignorant of what a regular expression was, I got a quick explanation from the programmer who brought it up, and then I quickly got Perl to do what I needed, learning how powerful regular expressions are. Regular expressions are like that magical elixir, that wonderful little secret that was created to fix specific little problems, and man when you need them, they do the job better than almost any other.

If you are reading this review, you probably have some background as to what regular expressions are, but in a nutshell, they quickly let you find a particular search string and then modify it as needed. Regular expressions have their own ruleset as to how these searches/replacements are performed, and in order to learn how to write good RegExs, you need the book 'Mastering Regular Expressions'. You will not find a Regular Expression reference as good as this book by Jeffery Friedl, and I challenge you to look for yourself!

If you ever need to parse through a lot of data, whether it be logs or just finding a particular piece of code, you will save yourself a lot of time and gain much in performance by learning how to use Regular Expressions to accomplish the task(s) at hand. Having this book by your side will make that journey all the easier, and you will find lots of great examples pre-written, and new approaches as to how to write better RegExs to complete your tasks by having this text by your side. It's binary folks, if you use RegExs in your line of work, you need this book, you will not be let down!!

***** HIGHEST RECOMMENDATION

How come a technology that is as old as computers themselves is still around? Regular expressions solve one of the most basic problems in computer science: parsing strings.
There is no doubt that regular expressions are beasts. This will will demystify them. By understanding them, you will be less scared of using them. This book does just that. However, the level of this book is high and the level of details amazing. It is not a cook book so it would be wise to also read another book that gives you more examples. This particular book is like the bible of regex. It needs to be in your library.

If you are an experienced programmer, then you have undoubtedly heard of the power behind regular expressions. Unfortunately, even for seasoned developers, becoming very proficient in regular expressions is no trivial task... or is it? Sure most regular expressions look very arcane and are even harder to write, but luckily there is at least one good resource to help bend the learning curve. I am talking about Mastering Regular Expressions by Jeffrey Friedl. This book breaks down regex to such a trivial level that you can't help but learn how to harness the regex power. Jeff takes you step by step through regex land and holds your hand throughout the whole trip. Next thing you know, you will be crafting high quality regular expressions and you will learn how to truly harness such a powerful tool.

Unfortunately in every programmers life there are mental blocks that keep us from truly progressing. For some it's pointers or OOP concepts and for others such as myself its regular expressions. This book took that mental block and smashed it, then it paved the way to regex land. Now I feel much better! HIGHLY recommended!

Jeffrey Friedl is the man whom I credit for getting my start in computer programming. I even sent him a thank you letter after reading his first edition. Once you take the time to learn Regular Expressions, you'll often wonder how you got by without them. There is no better book to teach you than this one.

[Review of 3rd edition]

I last reviewed this book in early 2005 when it was still in the second edition. But with the release of Jeffrey E. F. Friedl's Mastering Regular Expressions (3rd Edition), I thought it best to give it another look. It's still great, it's still the definitive guide to the subject, and now it gives PHP'ers more to work with...

Contents: Introduction to Regular Expressions; Extended Introductory Examples; Overview of Regular Expression Features and Flavors; The Mechanics of Expression Processing; Practical Regex Techniques; Crafting an Efficient Expression; Perl; Java; .NET; PHP; Index

As with the last edition, you'll find nearly everything you need to know about regular expressions here. Since the general rules of regular expressions haven't changed much, it's not as if you're trying to learn regex version 12.5. The main difference in this edition is that Friedl gave PHP a whole lot more coverage in this update. PHP has become more mainstream over the last year or so, and if that's your area of interest you'll find more examples and guidelines now. Java 1.5 and 1.6 have also emerged since the last writing, so there's a bit more clarification as to how regex coding has changed (not much).

My initial recommendation hasn't changed one bit... If you do anything with regular expressions in your programming, get this book, put your name in it, and don't let others borrow it...

Like the other Oriely books I've read, this book tells you everything you ever wanted to know about regex and probably a lot of stuff that is interesting but not practically nescary. This book covers regex egines and most common implimentation of regex. It's all good stuff but I would like a book that is more focussed on the practical details of this how you write a regex to validate a phone number or a data etc....

I found this book to be really useful. It was an easy to follow step by step descriptioon of the regular expression language. It also provided valuable insight into the regular expression evaluation engine which is critical to creating efficient and performant expressions.

A must read for anybody that wants to really write effective regular expressions.