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

r"
"
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 = "(/?ark:/? ?)([-a-zA-Z0-9@:%_\\+.~#?&//=]*)"; final String string = "https://www.example.com\n" + "http://www.example.com\n" + "www.example.com\n" + "example.com\n" + "http://blog.example.com\n" + "http://www.example.com/product\n" + "http://www.example.com/products?id=1&page=2\n" + "http://www.example.com#up\n" + "http://255.255.255.255\n" + "255.255.255.255\n" + "255.255.255.255/test\n" + "http://invalid.com/perl.cgi?key= | http://web-site.com/cgi-bin/perl.cgi?key1=value1&key2\n" + "http://www.site.com:8008\n" + "http://www.site.com:8008 10.1016.12.31/naTUrE.S0735-1097(98)2000/12/31/34:7-7 http://myrepo.example.org/ark:/12345/bcd987\n" + "http://n2t.net/ark:/12345/bcd987\n" + "http://texashistory.unt.edu/ark:/67531/metapth346793\n" + "http://example.org/ark:/12025/654xz321/s3/f8.05v.tiff\n" + "https://doi.org/10.3886/ICPSR06849 10.3886/ICPSR06849 https://www.icpsr.umich.edu/icpsrweb/NACJD/studies/6849/version/1\n" + "doi.org/10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2\n" + "ark: 12025/654xz321/s3/f8.05v.tiff\n" + " self.crossref_dois = (\n" + " '10.2310/JIM.0b013e31820bab4c',\n" + " '10.1007/978-3-642-28108-2_19',\n" + " '10.1016/S0735-1097(98)00347-7',\n" + " )\n\n" + " self.hard_dois = (\n" + " '10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2',\n" + " '10.1002/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S',\n" + " '10.1579/0044-7447(2006)35\\[89:RDUICP\\]2.0.CO;2',\n" + " )\n\n" + " self.currently_not_supported = (\n" + " '10.1007.10/978-3-642-28108-2_19',\n" + " '10.1000.10/123456',\n" + " '10.1016.12.31/nature.S0735-1097(98)2000/12/31/34:7-7',\n" + " )\n\n" + " self.crossref_dois = (\n" + " 'doi.org/10.2310/JIM.0b013e31820bab4c',\n" + " 'doi.org/10.1007/978-3-642-28108-2_19',\n" + " 'doi.org/10.1016/S0735-1097(98)00347-7',\n" + " )\n\n" + " self.hard_dois = (\n" + " 'doi.org/10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2',\n" + " 'doi.org/10.1002/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S',\n" + " 'doi.org/10.1579/0044-7447(2006)35\\[89:RDUICP\\]2.0.CO;2',\n" + " )\n\n" + " self.currently_not_supported = (\n" + " 'doi.org/10.1007.10/978-3-642-28108-2_19',\n" + " 'doi.org/10.1000.10/123456',\n" + " 'doi.org/10.1016.12.31/nature.S0735-1097(98)2000/12/31/34:7-7',"; 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