Regular Expressions 101

Save & Share

  • Regex Version: ver. 2
  • 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

/
/
gs

Test String

Code Generator

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"\[\@if(not)?:([a-zA-Z0-9]+)(?:=(.*?))?\].*?\[\@endif:\2\]"; string input = @"<!-- <h1>[!WLANSettings]</h1> --> [@if:examplevar=notgiven]this text won't show[@endif:examplevar] [@if:wlanena] [@if:wlanauto] <table id=""wlanavail"" class=""colorrows inputtable""> <tr id=""firstrow""> <th width=""30px""></th> <th width=""240px"">[!Name] (SSID)</th> <th width=""110px"">[!Encryption]</th> <th width=""150px"">[!SignalStrength]</th> <th width=""200px"">[!MAC]</th> </tr> <tr id=""loadingrow""> <td colspan=5 class=""centertext""><img src=""resources/loading.gif"" id=""loadingWlanScan""></td> </tr> <tr> <td></td> <td colspan=4><input type=""button"" id=""rescan"" value=""[!Refresh]"" style=""width: 200px""></td> </tr> </table> <p></p> [@endif:wlanauto] <table id=""wlansettings"" class=""inputTable""> <tr id=""wlannamerow"" [@if:wlanauto]style=""display: none;""[@endif:wlanauto]> <td>[!WLANName]</td> <td><input type=""text"" name=""wlanname"" id=""wlanname"" [@if:wlanauto]value=""[@wlanname]""[@endif:wlanauto] style=""width: 309px;""></td> </tr> <tr> <td>[!Password]:</td> <td><input type=""text"" name=""wlanpass"" id=""wlanpass"" style=""width: 309px;""></td> </tr> <tr> <td colspan=""2"" > <input type=""button"" [@if:wlanauto]id=""manualcfg"" name=""manualcfg"" value=""[!ManualConfig]""[@endif:wlanauto] [@ifnot:wlanauto]id=""autocfg"" name=""autocfg"" value=""[!AutomaticConfig]""[@endif:wlanauto] onclick=""handleMultiform(event, this);"" style=""width: 180px;""> </td> </tr> <tr> <td> <input type=""hidden"" name=""encinput"" id=""encinput"" value=""></td> <td id=""wlaninfo""></td> </tr> </table> [@ipsettings] [@endif:wlanena] [@ifnot:wlanena] [!NoWLANDevicePluggedIn] <p> <input type=""button"" name=""back"" onclick=""handleMultiform(event, this);"" value=""[!Back]"" /> </p> [@endif:wlanena] "; RegexOptions options = RegexOptions.Singleline; 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