Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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(`<a href=\"([^\"]+)\"[^/]*>([^<]*)<`) var str = `<p><a href="http://www.quackit.com/html/tutorial/html_links.cfm">Example Link</a></p> <div class="more-info"><a href="http://www.quackit.com/html/examples/html_links_examples.cfm">More Link Examples...</a></div> <li id="n-mainpage-description"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><b>Main page</b></a></li> <center> <div class="noresize" style="height: 242px; width: 600px; "><map name="ImageMap_1_971996215" id="ImageMap_1_971996215"> <area href="/wiki/File:Pardalotus_punctatus_female_with_nesting_material_-_Risdon_Brook.jpg" shape="rect" coords="3,3,297,238" alt="Female" title="Female" /> <area href="/wiki/File:Pardalotus_punctatus_male_with_nesting_material_-_Risdon_Brook.jpg" shape="rect" coords="302,2,597,238" alt="Male" title="Male" /></map><img alt="Pair of Spotted Pardalotes" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5b/Female_and_male_Pardalotus_punctatus.jpg/600px-Female_and_male_Pardalotus_punctatus.jpg" width="600" height="242" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5b/Female_and_male_Pardalotus_punctatus.jpg/900px-Female_and_male_Pardalotus_punctatus.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5b/Female_and_male_Pardalotus_punctatus.jpg/1200px-Female_and_male_Pardalotus_punctatus.jpg 2x" usemap="#ImageMap_1_971996215" /> <div style="margin-left: 0px; margin-top: -20px; text-align: left;"><a href="/wiki/File:Female_and_male_Pardalotus_punctatus.jpg" title="About this image"><img alt="About this image" src="//bits.wikimedia.org/static-1.22wmf7/extensions/ImageMap/desc-20.png" style="border: none;" /></a></div> </div> </center>` 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/