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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:github.com)(.*)"; final String string = "# [JSBox ](https://github.com/axelburks/JSBox?files=1) script\n" + "/\n" + " [Extract Scheme](https://github.com/axelburks/JSBox/tree/master/Extract%20Scheme) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/tree/master/Extract%20Scheme) [Launcher](https://github.com/axelburks/JSBox/tree/master/Launcher) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/tree/master/Launcher) [Magic Launcher](https://github.com/axelburks/JSBox/tree/master/Magic%20Launcher) \n" + " [8 months ago](https://github.com/axelburks/JSBox/tree/master/Magic%20Launcher) [Schedule Message](https://github.com/axelburks/JSBox/tree/master/Schedule%20Message) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/tree/master/Schedule%20Message) [XPin](https://github.com/axelburks/JSBox/tree/master/XPin) \n" + " [3 days ago](https://github.com/axelburks/JSBox/tree/master/XPin) [iTunes Utilities](https://github.com/axelburks/JSBox/tree/master/iTunes%20Utilities) \n" + " [6 months ago](https://github.com/axelburks/JSBox/tree/master/iTunes%20Utilities) [Boom.js](https://github.com/axelburks/JSBox/blob/master/Boom.js) \n" + " [almost 2 years ago](https://github.com/axelburks/JSBox/blob/master/Boom.js) [Clip Editor.js](https://github.com/axelburks/JSBox/blob/master/Clip%20Editor.js) \n" + " [about 1 year ago](https://github.com/axelburks/JSBox/blob/master/Clip%20Editor.js) [Downloader.js](https://github.com/axelburks/JSBox/blob/master/Downloader.js) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/blob/master/Downloader.js) [Emoji.js](https://github.com/axelburks/JSBox/blob/master/Emoji.js) \n" + " [almost 2 years ago](https://github.com/axelburks/JSBox/blob/master/Emoji.js) [IPA Installer.js](https://github.com/axelburks/JSBox/blob/master/IPA%20Installer.js) \n" + " [about 2 months ago](https://github.com/axelburks/JSBox/blob/master/IPA%20Installer.js) [Installer.js](https://github.com/axelburks/JSBox/blob/master/Installer.js) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/blob/master/Installer.js) [Pushbullet.js](https://github.com/axelburks/JSBox/blob/master/Pushbullet.js) \n" + " [about 1 year ago](https://github.com/axelburks/JSBox/blob/master/Pushbullet.js) [README.md](https://github.com/axelburks/JSBox/blob/master/README.md) \n" + " [about 2 months ago](https://github.com/axelburks/JSBox/blob/master/README.md) [SM.MS.js](https://github.com/axelburks/JSBox/blob/master/SM.MS.js) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/blob/master/SM.MS.js) [Shorten.js](https://github.com/axelburks/JSBox/blob/master/Shorten.js) \n" + " [about 1 year ago](https://github.com/axelburks/JSBox/blob/master/Shorten.js) [Thunder.js](https://github.com/axelburks/JSBox/blob/master/Thunder.js) \n" + " [about 1 year ago](https://github.com/axelburks/JSBox/blob/master/Thunder.js) [Tool Box play_icon.png](https://github.com/axelburks/JSBox/blob/master/Tool%20Box%20play_icon.png) \n" + " [almost 2 years ago](https://github.com/axelburks/JSBox/blob/master/Tool%20Box%20play_icon.png) [Tool Box.js](https://github.com/axelburks/JSBox/blob/master/Tool%20Box.js) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/blob/master/Tool%20Box.js) [Weico.js](https://github.com/axelburks/JSBox/blob/master/Weico.js) \n" + " [almost 2 years ago](https://github.com/axelburks/JSBox/blob/master/Weico.js) [XQRcode.js](https://github.com/axelburks/JSBox/blob/master/XQRcode.js) \n" + " [about 1 year ago](https://github.com/axelburks/JSBox/blob/master/XQRcode.js) [updateInfo](https://github.com/axelburks/JSBox/blob/master/updateInfo) \n" + " [over 1 year ago](https://github.com/axelburks/JSBox/blob/master/updateInfo) [version.json](https://github.com/axelburks/JSBox/blob/master/version.json) \n" + " [about 2 months ago](https://github.com/axelburks/JSBox/blob/master/version.json) "; final String subst = ""; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html