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

/
/
sg

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:|(?!^)\\G).*?<([^>]*)>(?=.*Message-ID)"; final String string = "Content-Type: application/ms-tnef; name=\"winmail.dat\"\n" + "Content-Transfer-Encoding: binary\n" + "From: ABC aa DDD <aaaa.b@abc.com>\n" + "To: DDDDD dd <sssss.r@abc.com>\n" + "CC: Rrrrr rrede <sssss.rv@abc.com>, Dsssssf V R\n" + " <dsdsdsds.vr@abc.com>, Psssss A <pssss.a@abc.com>, Logistics\n" + " <LOGISTICS@abc.com>, Gssss Bsss P <gdfddd.p@abc.com>\n" + "Subject: RE: [MyApps] (PRO-34604) PR for Additional Monitor allocation [CITS\n" + " Ticket:258849]\n" + "Thread-Topic: [MyApps] (PRO-34604) PR for Additional Monitor allocation\n" + " [CITS Ticket:258849]\n" + "Thread-Index: AQHRXMJHE6KqCFxKBEieNqGhdNy7Pp8XHc0A\n" + "Date: Mon, 1 Feb 2016 17:56:17 +0530\n" + "Message-ID: <B7F84439E634A44AB586E3FF2EA0033A29E27E47@JETWINSRVRPS01.abc.com>\n" + "References: <JA.101.1453963700000@myapps.abc.com>\n" + " <JA.101.1453963700000.978.1454311765375@myapps.abc.com>\n" + "In-Reply-To: <JIRA.450101.1453963700000.978.1454311765375@myapps.abc.com>\n" + "Accept-Language: en-US\n" + "Content-Language: en-US\n" + "X-MS-Has-Attach:\n" + "X-MS-Exchange-Organization-SCL: -1\n" + "X-MS-TNEF-Correlator: <B7F84439E634A44AB586E3FF2EA0033A29E27E47@JETWINSRVRPS01.abc.com>\n" + "MIME-Version: 1.0\n" + "X-MS-Exchange-Organization-AuthSource: TURWINSRVRPS01.abc.com\n" + "X-MS-Exchange-Organization-AuthAs: Internal\n" + "X-MS-Exchange-Organization-AuthMechanism: 04\n" + "X-Originating-IP: [1.1.1.7]"; final Pattern pattern = Pattern.compile(regex, Pattern.DOTALL); 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