This is an experimental “book” about regular expressions. It is largely visual and example-based, as opposed to most regex resources I found while I was learning. I also attempted to choose test cases that highlight some common gotchas. I think it’ll be worth your time.

This book’s intended audience is regex beginners. Some programming experience is assumed. It does not go into advanced regex concepts like engine backtracking and recursive regexes—at least not at the moment.

This is also an open source project, and contributions are welcome.

Contents

0. Introduction
1. Basics
2. Character Classes
3. Character Escapes
4. Escapes
5. Groups
6. Repetition
7. Alternation
8. Flags
9. Anchors
10. Lookaround
11. Advanced Examples
12. Next Steps