Mastering Regular Expressions   (book)

Mastering Regular Expressions

I find regular expressions (regexes) extremely useful. Some people love to bring up the quote "now they have two problems" whenever regexes are brought up. I think that quote is appropriate sometimes, but in many cases, regexes replace much larger sections of code and are much more readable and much less complex than said code.

This book is all about regular expessions, and the details behind the scenes. It has specific examples from several languages including Perl, Java, and .NET IIRC. I've already learned several interesting facts I didn't know before (you don't have to escape metacharacters inside character classes), so the book is already worth it to me.