Reference

Regex Cheatsheet

Categorized regex reference with 57+ patterns. Search to find what you need.

Character Classes

.Any character except newlinea.c matches "abc"

\dAny digit [0-9]\d+ matches "123"

\DAny non-digit\D+ matches "abc"

\wWord character [a-zA-Z0-9_]\w+ matches "hello_1"

\WNon-word character\W matches "!"

\sWhitespace character\s matches " "

\SNon-whitespace character\S+ matches "hello"

[abc]Character set[aeiou] matches vowels

[^abc]Negated character set[^0-9] matches non-digits

[a-z]Character range[a-z]+ matches "hello"

Anchors

^Start of string/line^Hello matches start

$End of string/lineworld$ matches end

\bWord boundary\bword\b exact word

\BNon-word boundary\Bword not at boundary

Quantifiers

*Zero or moreab*c matches "ac","abc"

+One or moreab+c matches "abc"

?Zero or onecolou?r matches both

{n}Exactly n times\d{3} matches "123"

{n,}n or more times\d{2,} matches "12","123"

{n,m}Between n and m times\d{2,4} matches "12"-"1234"

*?Lazy zero or more<.*?> non-greedy match

+?Lazy one or more.+? minimal match

Groups & Alternation

(abc)Capturing group(\d+) captures digits

(?:abc)Non-capturing group(?:ab)+ matches "abab"

(?<name>)Named capturing group(?<year>\d{4})

a|bAlternation (or)cat|dog matches either

\1Backreference(\w)\1 matches "aa"

Lookahead & Lookbehind

(?=abc)Positive lookahead\d(?=px) digit before px

(?!abc)Negative lookahead\d(?!px) digit not before px

(?<=abc)Positive lookbehind(?<=\$)\d+ after $

(?<!abc)Negative lookbehind(?<!\$)\d+ not after $

Flags

gGlobal search/pattern/g all matches

iCase insensitive/hello/i matches "HELLO"

mMultiline mode/^line/m each line start

sDotall (. matches \n)/a.b/s spans lines

uUnicode mode/\u{61}/u matches "a"

Common Patterns

^[\w.-]+@[\w.-]+\.\w{2,}$Email addressuser@example.com

^https?://[\w.-]+URLhttps://example.com

^\d{1,3}(\.\d{1,3}){3}$IPv4 address192.168.1.1

^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$Hex color#ff0000 or #f00

^\d{4}-\d{2}-\d{2}$Date (YYYY-MM-DD)2024-01-15

^\+?\d{1,3}[-.\s]?\d{3,}Phone number+1-555-1234

^\d{5}(-\d{4})?$US ZIP code12345 or 12345-6789

<[^>]+>HTML tag<div class="x">

\b\d{1,3}(,\d{3})*(\.\d+)?\bNumber with commas1,234,567.89

^(?=.*[A-Z])(?=.*[a-z])(?=.*\d).{8,}$Strong passwordMin 8, upper, lower, digit

Escaping

\.Escaped dot (literal .)file\.txt matches "file.txt"

\\Escaped backslashpath\\to matches "path\to"

$Escaped parenthesisf\(x$ matches "f(x)"

\[Escaped bracket\[0\] matches "[0]"

\{Escaped brace\{a\} matches "{a}"

\*Escaped asterisk2\*3 matches "2*3"

\+Escaped plusC\+\+ matches "C++"

\?Escaped question markwhy\? matches "why?"

\|Escaped pipea\|b matches "a|b"

\^Escaped caret\^start matches "^start"

\$Escaped dollar\$100 matches "$100"