Regex Mastery

This is the regex skill you wish you'd had when you were staring at `/^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}$/` at 2am wondering why it wasn't matching. It covers the fundamentals (greedy vs lazy, character classes, anchors) and the advanced stuff (named capture groups, lookarounds, catastrophic backtracking). The examples are practical: email validation, log parsing, phone number formats. What I appreciate most is the honesty about when not to use regex. It explicitly tells you to use a proper parser for HTML/XML and warns against trying to implement full RFC 5321 email validation. The emphasis on readability over cleverness and the push toward named groups will save future you from hating past you.