Regex Cheatsheet

Quick reference for regular expressions

Character Classes

.Any character except newlinea.c → abc, a1c

\dDigit (0-9)\d{3} → 123

\DNon-digit\D+ → abc

\wWord character (a-z, A-Z, 0-9, _)\w+ → hello_123

\WNon-word character\W → @, #, !

\sWhitespace\s+ → spaces/tabs

\SNon-whitespace\S+ → hello

[abc]Character set (a, b, or c)[aeiou] → vowels

[^abc]Negated set (not a, b, or c)[^0-9] → non-digits

[a-z]Range[A-Za-z] → letters

*0 or moreab*c → ac, abc, abbc

+1 or moreab+c → abc, abbc

?0 or 1 (optional)colou?r → color, colour

{n}Exactly n times\d{4} → 2024

{n,}n or more times\d{2,} → 12, 123, 1234

{n,m}Between n and m times\d{2,4} → 12, 123, 1234

*?Lazy (0 or more, minimal)<.*?> → first tag only

+?Lazy (1 or more, minimal).+? → minimal match

^Start of string/line^Hello → starts with Hello

$End of string/lineworld$ → ends with world

\bWord boundary\bcat\b → cat (not cats)

\BNon-word boundary\Bcat → scat, category

(abc)Capture group(\d+)-(\d+) → groups

(?:abc)Non-capturing group(?:ab|cd)+ → abcd

\1Backreference to group 1(\w)\1 → aa, bb

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

(a|b)Alternation (a or b)(cat|dog) → cat or dog

(?=abc)Positive lookahead\d+(?=px) → 10 in 10px

(?!abc)Negative lookahead\d+(?!px) → 10 not before px

(?<=abc)Positive lookbehind(?<=\$)\d+ → 10 in $10

(?<!abc)Negative lookbehind(?<!\$)\d+ → 10 not after $

[\w.-]+@[\w.-]+\.\w+Emailuser@example.com

https?://[\w.-]+(/\S*)?URLhttps://example.com/path

\d{3}-\d{3}-\d{4}US Phone123-456-7890

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

#[0-9A-Fa-f]{6}Hex Color#FF5733

\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}IPv4192.168.1.1