What is a regular expression (regex)?▼
A regular expression is a pattern used to match character combinations in strings. It's used in programming, text editors, and command-line tools for searching, validating, and replacing text.
What do the flags mean?▼
g = global (find all matches, not just first), i = case insensitive, m = multiline (^ and $ match line start/end), s = dotall (. matches \n too).
Why is my regex not matching?▼
Common issues: forgetting the global flag (g) for multiple matches, not escaping special characters (., *, +, etc.), and not enabling multiline for line-by-line matching.
Can I use this for Indian IDs?▼
Yes! We have presets for PAN card, Aadhaar number, Indian phone numbers, and more. Click any preset to load the pattern and test data.