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

/
/
im

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 = "(http:\\/\\/dx.doi.org\\/10|10| DOI: 10|DOI:10).\\d{4,9}\\/[-._;()\\/:0-9]+"; final String string = "Small Group Research2014, Vol. 45(6) 671 Œ703© The Author(s) 2014Reprints and permissions:sagepub.com/journalsPermissions.nav DOI: 10.1177/1046496414552285sgr.sagepub.comArticleA Conceptual Review of Emergent State \n" + "Measurement: Current \n" + "Problems, Future \n" + "SolutionsChris W. Coultas1, Tripp Driskell2, C. Shawn Burke1, and Eduardo Salas1AbstractTeam research increasingly incorporates emergent states as an integral \n" + "mediator between team inputs and outcomes. In conjunction with this, we \n\n" + "have witnessed a proliferation and fragmentation of measurement techniques \n\n" + "associated with emergent states. This inconsistency in measurement presents \n" + "a problem for scientists and practitioners alike. For the scientist, it becomes \n" + "difficult to better understand the nature and effects of various emergent \n\n" + "states on team processes and outcomes. For the practitioner, it complicates \n" + "the process of measurement development, selection, and implementation. \n" + "To address these issues, we review the literature on emergent states focusing \n" + "on various measurement strategies, to better unpack best practices. In so \n" + "doing, we highlight existing research that suggests innovative solutions to the \n" + "conceptual, methodological, and logistical problems that consistently plague \n" + "emergent state research. Our aim is to enhance emergent state theory by \n" + "applying psychometric principles to the measurement techniques associated \n" + "with them.1University of Central Florida, Orlando, USA2The Florida Maxima Corporation, Orlando, USACorresponding Author:Chris W. Coultas, University of Central Florida, 4000 Central Florida Blvd., Psychology Bldg. \n" + "99, Ste. 320, Orlando, FL 32816, USA. \n" + "Email: ccoultas@ist.ucf.eduThis article is part of the special issue: 2014 Annual Review Issue, Small Group Research, Volume 45(6).552285SGRXXX10.1177/1046496414552285\n" + "Small Group ResearchCoultas et al.research-article\n" + "2014\n"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); if (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