Regex Cheatsheet - Regular Expression Quick Reference
Quick reference for regular expression patterns. Character classes, quantifiers, anchors, and common patterns.
Negative Lookahead (?!abc)
AssertionMatches position NOT followed by specified expression
Pattern
(?!abc)Syntax
Explanation
Negative lookahead excludes matches followed by a specific pattern.
Examples
\d{3}(?!-)Match 3 digits not followed by hyphen
Matches: 123, 456
\b(?!un)\w+\bMatch words not starting with "un"
Matches: happy, kind
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