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

/
/
gmi

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?:<[pP]>)?(?:<strong>)(?:<br \/>)?(?:<[aA]\s\w+=""([?0-9–\-\/\wÅåÄäÖö;,.()\[\]&\s]+)"">(?:<\/[aA]>)?)([?0-9–\-\/\wÅåÄäÖö;,.()\[\]&\s]+)(?:<\/strong>)([?0-9–\-\/\wÅåÄäÖö;,.()\[\]&\s]+)"; string substitution = @"<p><strong><a name=""$1"">$2</a></strong>$3</p>"; string input = @"<strong><A NAME=""Bondeupproret""></A>Andersson, Per,</strong> Bondeupproret i Sk&aring;ne 1811 / Per Andersson, Arne Ribnell. – [Ny, ut&ouml;kad uppl.]. – Malm&ouml;, 1996. – 12 s. <p><strong><br />Andersson, Per,</strong> Litteratur om Svedalatrakten. – Malm&ouml;[?], 197-. – 6 bl. <p><strong><br /><A NAME=""borgar_slott""></A>Andersson, Per,</strong> Sk&aring;nska borgar, slott och herrg&aring;rdar. – Lund, 1996. – 212 s. <p><strong><br /><A NAME=""Skånska_kyrkor""></A>Andersson, Per,</strong> Sk&aring;nska kyrkor, kapell, kloster och andra kyrkliga byggnader. – Malm&ouml;, 1985. – 254 s. <p><strong><br /><A NAME=""Att_läsa""></A>Ericsson, Acke,</strong> Att l&auml;sa om Sturup. // SkNK. – 1973, h. 1, s. 37-40. <br />Urval ur Acke Ericssons bibliografi, se nedan. <p><strong><br /><A NAME=""Sturup""></A>Ericsson, Acke,</strong> Sturup. – Malm&ouml;, 1973. – 24 bl. <p><strong><br />J&ouml;nsson, Knut,</strong> Anteckningar till en bibliografi &ouml;ver Bara kommun. – Bor&aring;s, 1975. – 76 bl. "; RegexOptions options = RegexOptions.Multiline | RegexOptions.IgnoreCase; Regex regex = new Regex(pattern, options); string result = regex.Replace(input, substitution); } }

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