Regular Expressions (Regex) Guide

Regular Expressions Guide is the reference every developer needs when working with text matching, validation, and parsing. Regex syntax is powerful but easy to forget — keep this guide handy. What's inside: - Regex syntax fundamentals: literals, metacharacters, escaping - Character classes: [abc], [^abc], shorthand classes \d \w \s - Quantifiers: *, +, ?, {n}, {n,m}, greedy vs lazy - Anchors: ^ $ \b \B - Groups: capturing, non-capturing, named groups - Alternation and backreferences - Lookahead and lookbehind assertions - Flags: global, case-insensitive, multiline, dotall - Python re module reference - JavaScript regex reference - 50+ real-world regex patterns: email, URL, IP, date, phone, password validation