/^/Regex Library

Open Playground

Regex Cheat Sheet

Every token, quantifier, and assertion you'll need — copyable and printable.

Anchors

Token	Meaning	Example
^	Start of string (or line, with the m flag)	^Hello
$	End of string (or line, with the m flag)	world$
\b	Word boundary	\bcat\b
\B	Not a word boundary	\Bcat\B

Character Classes

Token	Meaning	Example
.	Any character except line breaks	a.c
\d	Any digit (0-9)	\d{3}
\D	Any non-digit	\D+
\w	Any word character (letter, digit, underscore)	\w+
\W	Any non-word character	\W
\s	Any whitespace character	\s+
\S	Any non-whitespace character	\S+
[abc]	Any of a, b, or c	[abc]
[^abc]	Any character except a, b, or c	[^abc]
[a-z]	Any character in the range a to z	[a-z]+

Quantifiers

Token	Meaning	Example
*	Zero or more (greedy)	ab*
+	One or more (greedy)	ab+
?	Zero or one (optional)	colou?r
{n}	Exactly n times	\d{4}
{n,}	n or more times	\d{2,}
{n,m}	Between n and m times	\d{2,4}
*?	Zero or more (lazy)	<.*?>
+?	One or more (lazy)	".+?"

Groups & Backreferences

Token	Meaning	Example
(...)	Capturing group	(ab)+
(?:...)	Non-capturing group	(?:ab)+
(?<name>...)	Named capturing group	(?<year>\d{4})
\1	Backreference to group 1	(\w)\1
\k<name>	Backreference to a named group	(?<q>['"])\k<q>
\|	Alternation (OR)	cat\|dog

Lookaround Assertions

Token	Meaning	Example
(?=...)	Positive lookahead	\d+(?=px)
(?!...)	Negative lookahead	\d+(?!px)
(?<=...)	Positive lookbehind	(?<=\$)\d+
(?<!...)	Negative lookbehind	(?<!\$)\d+

Escaping

Token	Meaning	Example
\.	Literal dot	3\.14
\\	Literal backslash	C:\\\\Users
\/	Literal forward slash	https:\/\/
\(	Literal opening parenthesis	\(\d{3}\)
\[	Literal opening bracket	\[note\]

Unicode

Token	Meaning	Example
\p{L}	Any Unicode letter (needs u flag)	\p{L}+
\p{N}	Any Unicode number (needs u flag)	\p{N}+
\p{Emoji}	Any emoji character (needs u/v flag)	\p{Emoji}
\u{1F600}	Unicode code point escape (needs u flag)	\u{1F600}

Flags

Token	Meaning	Example
g	Global — find all matches, not just the first	—
i	Case-insensitive matching	—
m	Multiline — ^ and $ match line boundaries	—
s	Dot-all — . also matches newlines	—
u	Unicode — enables full Unicode matching	—
y	Sticky — matches only from lastIndex	—