📖 Regular Expression (Regex) Syntax & Matcher Guide
Master regex patterns, character classes, quantifiers, lookahead assertions, and flags (g, i, m, s, u).
Core Concepts of Regular Expressions
Regular Expressions (RegExp) are sequence patterns used to match character combinations within text strings. They are widely used for data validation, string parsing, and search-and-replace operations.
Key regex tokens include character sets (`[a-z]`), anchors (`^` for start, `$` for end), quantifiers (`*`, `+`, `?`, `{n,m}`), and capture groups (`(...)`).
Frequently Asked Questions
Detailed specifications & guides FAQs.