Regex Cheat Sheet

Regular expression syntax reference — character classes, quantifiers, anchors, groups, and lookarounds.

Character Classes

.Any character except newline

Digit\dDigit [0-9]

Non-digit\DNon-digit

Word\wWord char [a-zA-Z0-9_]

Non-word\WNon-word char

Space\sWhitespace

Non-space\SNon-whitespace

Set[abc]Any of a, b, or c

Negated set[^abc]Not a, b, or c

Range[a-z]Range a to z

Quantifiers

Star*0 or more

Plus+1 or more

Optional?0 or 1

Exact{n}Exactly n

Min{n,}n or more

Range{n,m}Between n and m

Lazy star*?0 or more (lazy)

Lazy plus+?1 or more (lazy)

Anchors & Boundaries

Start^Start of string

End$End of string

Boundary\bWord boundary

Non-boundary\BNon-word boundary

Groups & References

Group(abc)Capture group

Non-capture(?:abc)Non-capture group

Named(?<name>abc)Named group

Back-ref\1Back-reference

Ora|bAlternation (OR)

Lookaheads & Lookbehinds

Lookahead(?=abc)Positive lookahead

Neg lookahead(?!abc)Negative lookahead

Lookbehind(?<=abc)Positive lookbehind

Neg lookbehind(?<!abc)Negative lookbehind

Common Patterns

Email[\w.-]+@[\w.-]+\.\w+

URLhttps?://[\w.-]+(?:/[\w./-]*)?

IPv4\d{1,3}(\.\d{1,3}){3}

Hex color#[0-9a-fA-F]{3,8}

Phone (US)$?\d{3}$?[-.\s]?\d{3}[-.\s]?\d{4}

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