Regular expressions (regex) are powerful tools for pattern matching and text manipulation. Here's a breakdown of advanced concepts:
1. Character Classes & Ranges
Use [a-zA-Z0-9] to match any alphanumeric character. For ranges, write a-z for lowercase letters.
2. Grouping & Capturing
Enclose patterns in () to group them. Captured groups can be referenced later using \1, \2, etc.
3. Greedy vs Lazy Matching
Greedy quantifiers like * and + match as much as possible. Add a ? to make them lazy: *? or +?.
4. Positive & Negative Lookaheads
Use (?=pattern) to assert a pattern ahead. (?!\w+\b) checks for absence of a word boundary.
5. Backreferences & Substitutions
Replace text with captured groups using $1, $2, etc. Example: s/(^\w+) \w+/$1/ for abbreviation.
For deeper exploration, check our Regex Basics Guide to build foundational knowledge. 📚