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

/
/
gm

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 = "\\\"apps\\\"\\s+\\{\\s+(\\\"(\\d+)\\\"\\s+\\\"\\d+\\\"\\s+)+\\s+\\}"; final String string = "\"libraryfolders\"\n" + "{\n" + " \"0\"\n" + " {\n" + " \"path\" \"C:\\\\Program Files (x86)\\\\Steam\"\n" + " \"label\" \"\"\n" + " \"contentid\" \"-4617057559629097284\"\n" + " \"totalsize\" \"0\"\n" + " \"update_clean_bytes_tally\" \"26071119336\"\n" + " \"time_last_update_corruption\" \"0\"\n" + " \"apps\"\n" + " {\n" + " \"228980\" \"419015490\"\n" + " \"250820\" \"5600094877\"\n" + " \"705900\" \"2514926917\"\n" + " }\n" + " }\n" + " \"1\"\n" + " {\n" + " \"path\" \"N:\\\\SteamLibrary\"\n" + " \"label\" \"\"\n" + " \"contentid\" \"3764071818320917735\"\n" + " \"totalsize\" \"1000186310656\"\n" + " \"update_clean_bytes_tally\" \"225615218162\"\n" + " \"time_last_update_corruption\" \"0\"\n" + " \"apps\"\n" + " {\n" + " \"221680\" \"7000427217\"\n" + " \"223750\" \"221071349004\"\n" + " \"223850\" \"3121585480\"\n" + " \"236390\" \"45325788243\"\n" + " \"348250\" \"2996347031\"\n" + " \"438100\" \"832697714\"\n" + " \"450390\" \"16625763869\"\n" + " \"546560\" \"72900756522\"\n" + " \"578080\" \"35943596276\"\n" + " \"667970\" \"2603561151\"\n" + " \"690790\" \"117594033997\"\n" + " \"1118240\" \"2213415708\"\n" + " \"1174180\" \"128249349313\"\n" + " \"1250410\" \"1865648550\"\n" + " \"1255560\" \"9741578437\"\n" + " \"1517290\" \"66609320436\"\n" + " }\n" + " }\n" + "}\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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