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

/
/
g

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 = "PC\\D*((([\\dA-Z]{5})-){4}\\g<3>)"; final String string = "PC: WW533-S5T3B-53JJB-JTBT3-WZRBH\n" + "PS3: WW533-S5T3C-39JKB-STCT3-WZRRS\n" + "XBOX: WW533-S5T6F-65RJF-KXBT3-WZRW9\n\n" + "PC: CCCBB-X5JTB-5BB33-TJ3BJ-SK3KR\n" + "PS3: CCCBB-X5JTC-3HB53-ZJ5BJ-SK3ST\n" + "XBOX: CCCBB-X5JXF-6CF36-WR3BJ-SK3XW\n\n" + "PC: 5CKBB-K53BJ-CJTTT-JTJ3B-BHCSJ\n" + "PS3: 5CKBB-K53BK-BSTWT-STK3B-BHCTZ\n" + "XBOX: 5CKBB-K53FR-FKXTX-KXJ3B-BHCFW\n" + "PC: 5WWBJ-TWBJJ-KT3JB-TJBBB-CJ5KJ\n" + "PS3: 5WWBJ-TWBJK-JZ3KB-ZJCBB-CJ555\n" + "XBOX: 5WWBJ-TWBRR-RW6JF-WRBBB-CJ5T9\n" + "BL: TPS 1 GK: PS3: WCWBT-S3TTK-BSJK3-HT5TB-TWR9W WinPC/Mac/Linux: WCWBT-S3TTJ-CJJJ3-BT3TB-TWRWZ X360: WCWBT-S3TXR-FKRJ6-CX3TB-TWR3R\n\n" + "BL: TPS 1 GK: PS3: C5KTB-RTJ35-B93WT-HBKBB-WZWBX WinPC/Mac/Linux: C5KTB-RTJ33-C33TT-BBJBB-WZWJX X360: C5KTB-RTJ66-F56TX-CFJBB-WZWX5\n\n" + "BL: TPS 1 GK: PS3: C5CJB-WTT3W-TSJCT-ST5JJ-CKJKX WinPC/Mac/Linux: C5CJB-WTT3T-WJJBT-JT3JJ-CKJZ3 X360: C5CJB-WTT6X-XKRBX-KX3JJ-CKJZX\n\n" + "Nov 13\n" + "The Pre-Sequel:\n" + "PS3: C5CTT-3JJJK-B9JWJ-S35BJ-SZ99H WinPC/Mac/Linux: C5CTT-3JJJJ-C3JTJ-J33BJ-SZ9SK X360: C5CTT-3JJRR-F5RTR-K63BJ-SZ9KW\n\n" + "BL:TPS GK:\n" + "PS3: WW533-S5T3C-39JKB-STCT3-WZRRS\n" + "WinPC/Mac/Linux: WW533-S5T3B-53JJB-JTBT3-WZRBH\n" + "X360: WW533-S5T6F-65RJF-KXBT3-WZRW9"; 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