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

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(/?ark:/? ?)([-a-zA-Z0-9@:%_\+.~#?&//=]*)"; string input = @"https://www.example.com http://www.example.com www.example.com example.com http://blog.example.com http://www.example.com/product http://www.example.com/products?id=1&page=2 http://www.example.com#up http://255.255.255.255 255.255.255.255 255.255.255.255/test http://invalid.com/perl.cgi?key= | http://web-site.com/cgi-bin/perl.cgi?key1=value1&key2 http://www.site.com:8008 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 http://n2t.net/ark:/12345/bcd987 http://texashistory.unt.edu/ark:/67531/metapth346793 http://example.org/ark:/12025/654xz321/s3/f8.05v.tiff https://doi.org/10.3886/ICPSR06849 10.3886/ICPSR06849 https://www.icpsr.umich.edu/icpsrweb/NACJD/studies/6849/version/1 doi.org/10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2 ark: 12025/654xz321/s3/f8.05v.tiff self.crossref_dois = ( '10.2310/JIM.0b013e31820bab4c', '10.1007/978-3-642-28108-2_19', '10.1016/S0735-1097(98)00347-7', ) self.hard_dois = ( '10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2', '10.1002/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S', '10.1579/0044-7447(2006)35\[89:RDUICP\]2.0.CO;2', ) self.currently_not_supported = ( '10.1007.10/978-3-642-28108-2_19', '10.1000.10/123456', '10.1016.12.31/nature.S0735-1097(98)2000/12/31/34:7-7', ) self.crossref_dois = ( 'doi.org/10.2310/JIM.0b013e31820bab4c', 'doi.org/10.1007/978-3-642-28108-2_19', 'doi.org/10.1016/S0735-1097(98)00347-7', ) self.hard_dois = ( 'doi.org/10.1175/1520-0485(2002)032<0870:CT>2.0.CO;2', 'doi.org/10.1002/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S', 'doi.org/10.1579/0044-7447(2006)35\[89:RDUICP\]2.0.CO;2', ) self.currently_not_supported = ( 'doi.org/10.1007.10/978-3-642-28108-2_19', 'doi.org/10.1000.10/123456', 'doi.org/10.1016.12.31/nature.S0735-1097(98)2000/12/31/34:7-7',"; RegexOptions options = RegexOptions.Multiline; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx