Mastering Regular Expressions

Most regex books, blogs, websites, tutorials and classes cover “just the basics” really. Even the ones that say “advanced” often barely get into lookarounds.This book is the definitive guide on regex. Full stop. I’m not quite halfway through and it has already increased my understanding of regex in ways I hadn’t imagined possible. That said, the 3rd edition is 16 years old and it shows. The author regularly references now out-of-date technologies (e.g., PHP and Tcl). But that in no way hampers his ability to teach and ingrain the material. One just simply needs to understand that due to its age, some claims may no longer be true.For example, (and bare in mind I’m halfway through so I don’t know what I don’t yet know) there’s a chart stating that MySQL’s regex engine is a DFA. From what I’ve read, and knowing that MySQL “upgraded” their regex support in version 8, I believe it may now be an NFA. Or, at the very least, a hybrid. I could be wrong, but the point is, before reading this book, I wouldn’t have understood enough to even make that guess.Now, will I skip the chapters that focus on PHP and Tcl? Perhaps the latter. It’s not like I can’t come back and read it later if I find myself ankle-deep in Tcl regex one day. I could say the same for PHP, but it’s in a lot of legacy software, so a quick read through it is probably worthwhile.Not to keep bringing it up, but even halfway through, my understanding of lookarounds increased substantially. I use all of them regularly, but with a half-understanding of what was going on or why it would work sometimes and others not. Beyond that, greedy/lazy/possessive quantifiers… grouping. Sure, I’ve used them at some point. Some more often than others and with more understanding. But now? I get it all.It’s kind of a shame. I don’t have to write regex every day and when I do, it’s usually file searching, so it’s throw-away code. However, I haven’t yet read the chapters on efficiency, so perhaps my knowledge will grow in that area and that will pay off daily!Anyway, if you have any regular use of regex, this book is worth it. I picked up a used copy. I’d have paid cover price ($44.99 USD) easily knowing what’s actually in the book, how it’s written, etc. That brings me to my final point. The author does an amazing job of keeping what could be a very dry subject fresh and clear. You just can’t appreciate that enough.

I use to google "regex" and refer to the websites that would show from the search results. In my opinion, most of these sites were hard to use when trying to really understand regex. Maybe I wasn't persistent enough to screen crawl through several regex webpages/websites. I knew in my very soul I didn't understand regex well, because of constant issues coming up with seemingly easy regular expressions. I finally decided I wanted something comprehensive to learn regex.This book gave me the level of understanding I was looking for. After reading this book I can confidently say that I'm 1000% more comfortable reading and creating my own regex. I stopped once I reached chapter 7 because the last chapters, 7-10 are language specific chapters, but in the future I'll definitely refer back to those chapters once I'm working with those languages.Lastly, I did get some flak from other devs while I was reading this book "Geez you're reading a book on regex?? wow that's too boring for me." etc. etc. Don't listen to the haters! If you want a greater understanding of regex, and this book can get you there then don't listen to those nerds. At the end of the day and with learning anything, it only matters that the nerd in your shoes understands the subject. Also, take your time reading the book. It's perfectly fine to pace yourself and take more time reading, because there's a lot of needed detail.

This book is the best regular expression book out there. I've been writing software for several years and my practical experience didn't scratch the surface of what regular expressions can do and how they work.If you want to decipher complex regular expressions and write your own, this is THE book to read. Friedl never glosses over important points and he never makes assumptions that you already understand regular expressions. The fact is, most of us just don't. Although regular expressions is mostly a pretty dry topic, Friedl does a good job lightening things up here and there (enough to prevent the topic from being too dry, but not so much that we forget the serious nature of the subject matter).The typographic conventions are nothing short of groundbreaking, and I believe there is no other volume out there, on the web, or written that does as good of a job walking you through regular expressions, explaining how all the various parts work together and how to do things in your own practical way.This book teaches you to THINK in regular expressions. Those once cryptic symbols will become powerful tools for you to manipulate and get the results you need. For me, regular expressions were a bit of stumbling block and a possible security risk (since I couldn't decipher really complex regular expressions). Aside from that, I didn't know the difference between NFA, DFA, and Posix NVA or how to optimize regex for these various engines (or whether optimization is even needed).I strongly recommend this book for both beginners and veterans of regular expressions. It might not change your life, but it will change the way you read and write regular expressions.

This book has to be one of the best technical books I've read in many years. The author has gone to great lengths to explain how regular expressions work. The simple language allows the reader to understand and follow his train of thought. REGEX examples are all based on Perl, and you might find this annoying. However, I write simple scripts in Python and can follow the logic, so I re-write the examples. I wish everyone wrote technical books like Mastering Regular Expressions. Thank you, Jeffrey, for such a fantastic book.

Ensina com maestria coisas que eu não sabia que não sabia. Não se limita a ensinar expressões regulares para o uso cotidiano; mostra também como as expressões são processadas e compara explicando a diferença de performance de diferentes patterns.

... para cualquier lenguaje de programación

Probably the best tome on Regex there is. Covers just about every Regex flavor there is and their nuances. Reading through just a few chapters should whip you into good enough shape to apply intermediate to complex Regex patterns to the most common scenarios.Friedl exposes the internals of the most common Regex engine implementations.Whether you apply Regexes now and then, are a sysadmin, or are ramping up on work that demands Regex smarts, you will benefit greatly from this book.

Great book if you are serious about regex. Really liked the educational approach by starting simple and then progressing to challenging questions.(STARS){5}+