Regular Expressions 101

Save & Manage Regex

  • Current Version: 1
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
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
Processing...

Test String

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 = "to=<(?P<email>\\S+)>,\\srelay=(?!10\\.10\\.10\\.).+dsn=(?P<dsn>\\d+\\.\\d+\\.\\d+),\\sstatus=(?!sent)"; final String string = "2016-10-17T00:00:00.028777+03:00 postfix/smtp[6628]: 878A13DCA5: to=<govorok@gmail.com>, relay=gmail-smtp-in.l.google.com[173.194.220.27]:25, delay=0.47, delays=0.01/0/0.12/0.35, dsn=2.0.0, status=sent (250 2.0.0 OK 1476651600 79si16679285lja.36 - gsmtp)\n" + "2016-10-17T00:00:00.029273+03:00 postfix/qmgr[4674]: 878A13DCA5: removed\n" + "2016-10-17T00:00:00.037122+03:00 postfix/smtpd[6697]: 0906DA5: client=unknown[192.168.2.74]\n" + "2016-10-17T00:00:00.039621+03:00 postfix/cleanup[6713]: 0906DA5: message-id=<20161016210000.0906DA5@mrelay-h3.hh.ru>\n" + "2016-10-17T00:00:00.040403+03:00 postfix/smtp[6690]: C5670B9: to=<daler_rajabov@inbox.ru>, relay=mxs.mail.ru[217.69.139.150]:25, delay=0.23, delays=0.01/0/0.02/0.2, dsn=2.0.0, status=1s3ent (250 OK id=1bvsXH-0003Cb-Rp)"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html