Regex Cheat Sheet: Essential Regular Expressions for Beginners

Regular expressions (regex) are patterns used to match character combinations in strings. They are powerful tools for text processing, validation, and data extraction.

Basic Syntax

Anchors

• ^ — Start of string
• $ — End of string
• \b — Word boundary

Character Classes

• . — Any character except newline
• \d — Any digit (0-9)
• \w — Any word character (a-z, A-Z, 0-9, _)
• \s — Any whitespace
• [abc] — Any of a, b, or c
• [^abc] — Not a, b, or c
• [a-z] — Range from a to z

Quantifiers

• • — 0 or more
• • — 1 or more
• ? — 0 or 1
• {3} — Exactly 3
• {3,} — 3 or more
• {3,6} — Between 3 and 6

Useful Regex Patterns

Email Validation

Pattern: ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,}$

Phone Number (US)

Pattern: ^(?\d{3})?[-.\s]?\d{3}[-.\s]?\d{4}$

URL

Pattern: https?://[\w-]+(.[\w-]+)+[/\w-._~:?#[]@!$&()+,;=]

Strong Password

Pattern: ^(?=.[a-z])(?=.[A-Z])(?=.\d)(?=.[@$!%?&])[A-Za-z\d@$!%?&]{8,}$

Requires: lowercase, uppercase, digit, special character, minimum 8 characters.

Tips for Using Regex

1. Start simple and build up complexity
2. Test your patterns with online regex testers
3. Use non-capturing groups (?:…) when you do not need the match
4. Comment complex patterns for future readability
5. Use our Find & Replace tool with regex support for quick text processing