Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

r"
"
g

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`((D|O|0|3|\}|>|\*\<\||\|)?(%|#|\||x|X|B|8|:|;|\=)('|")?(\^|c|-|‑|o|っ)?(D|\)|\(|c|<|\[|\]|C|{|}|\||\&|>|\||3|Þ|þ|b|p|P|o|O|J|L|S|s|X|\\|\.|/|\$|\*|#|@))`) var str = `:( Hello! Howdy :)! Are you there :P? I'm fine :) :p :O :3 :| :/ :\ :$ :* :@ :( :-( :-) :-P :-p :-O :-3 :-| :-/ :-\ :-$ :-* :-@ :^( :^) :^P :^p :^O :^3 :^| :^/ :^\ :^$ :^* :^@ ): (: $: *: )-: (-: $-: *-: )^: (^: $^: *^: <3 </3 <\3 :‑) :) :D :o) :-) :] :3 :c) :> :-& =] 8) =) :} :^) :‑D 8‑D 8D x‑D xD X‑D XD =‑D =D =‑3 =3 B^D :-)) >:[  :‑(  :(  :‑c :c  :-<  :っC  :<  :-<  :‑[  :[  :{ ;( :-|| :@ >:( :'‑(  :"( :"-( :'( :'‑)  :') D:< D: D8 D; D= DX v.v D‑': :'-D >:O  :‑O  :O  :‑o  :o 8‑0 O_O o‑o O_o o_O o_o owo Owo OwO ouo OuO O-O :*  :^* ;‑) ;) ;‑]  ;] ;D ;^) >:P :‑P :P X‑P x‑p xp XP :‑p :p =p :‑Þ :Þ :þ :‑þ :‑b :b d: >:\ >:/ :‑/ :‑. :/ :\ :L =/ =\ :L =L :S >.< >/< >//< >///< :| :‑| :$ :‑X :X :‑# :# O:‑) 0:‑3 0:3 0:‑) 0:) 0;^) >:) >;) >:‑) }:‑) }:) 3:‑) 3:) >_> ^ ^ ^_^ ^_< >_^ <_< |;-) |-O :-J :-& :& #-) #) %-) %) :| :o| :-| ಠ_ಠ :-\ *<|:-) <3 </3 ˊ_>ˋ ` for i, match := range re.FindAllString(str, -1) { fmt.Println(match, "found at index", i) } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/