Regular Expressions 101

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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"
"

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"<th(?:| | .*?)>\s*<a(?:| | .*?)>\s*([\d.]+)\s*</a>\s*</th>\s*<td(?:| | .*?)>\s*stable\s*</td>"; string input = @" <table cellpadding=""2"" cellspacing=""1"" style=""width: 100%; border: 0px;""> <tr style=""background-color: #CCCCCC;""> <th colspan=""5"">Available Releases</th> </tr> <tr> <th valign=""top"" bgcolor=""#ffffff"">Version</th> <th valign=""top"" bgcolor=""#ffffff"">State</th> <th valign=""top"" bgcolor=""#ffffff"">Release Date</th> <th valign=""top"" bgcolor=""#ffffff"">Downloads</th> <th valign=""top"" bgcolor=""#ffffff"">&nbsp;</th> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/5.1.2"">5.1.2</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">stable</td> <td valign=""top"" bgcolor=""#e8e8e8"">2015-12-07</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-5.1.2.tgz"">apcu-5.1.2.tgz</a> (105.7kB)</td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=5.1.2"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.10"">4.0.10</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">stable</td> <td valign=""top"" bgcolor=""#e8e8e8"">2015-12-07</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.10.tgz"">apcu-4.0.10.tgz</a> (116.5kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.10/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.10"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/5.1.0"">5.1.0</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2015-11-21</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-5.1.0.tgz"">apcu-5.1.0.tgz</a> (106.8kB)</td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=5.1.0"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.8"">4.0.8</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">stable</td> <td valign=""top"" bgcolor=""#e8e8e8"">2015-11-20</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.8.tgz"">apcu-4.0.8.tgz</a> (116.3kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.8/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.8"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.7"">4.0.7</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2014-10-11</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.7.tgz"">apcu-4.0.7.tgz</a> (115.9kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.7/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.7"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.6"">4.0.6</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2014-06-12</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.6.tgz"">apcu-4.0.6.tgz</a> (116.9kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.6/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.6"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.5"">4.0.5</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2014-06-11</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.5.tgz"">apcu-4.0.5.tgz</a> (116.9kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.5/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.5"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.4"">4.0.4</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2014-03-01</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.4.tgz"">apcu-4.0.4.tgz</a> (116.9kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.4/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.4"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.3"">4.0.3</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2014-01-27</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.3.tgz"">apcu-4.0.3.tgz</a> (116.9kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.3/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.3"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.2"">4.0.2</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2013-09-14</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.2.tgz"">apcu-4.0.2.tgz</a> (117.5kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.2/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.2"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.1"">4.0.1</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2013-04-30</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.1.tgz"">apcu-4.0.1.tgz</a> (103.4kB)&nbsp;&nbsp;<a href=""/package/APCu/4.0.1/windows""><img src=""/gifs/windows-icon.png"" />DLL</a></td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.1"">Changelog</a>]</small></td> </tr> <tr> <th valign=""top"" bgcolor=""#cccccc""><a href=""/package/APCu/4.0.0"">4.0.0</a></th> <td valign=""top"" bgcolor=""#e8e8e8"">beta</td> <td valign=""top"" bgcolor=""#e8e8e8"">2013-03-26</td> <td valign=""top"" bgcolor=""#e8e8e8""><a href=""/get/apcu-4.0.0.tgz"">apcu-4.0.0.tgz</a> (101.8kB)</td> <td valign=""top"" bgcolor=""#e8e8e8""><small>[<a href=""/package-changelog.php?package=APCu&release=4.0.0"">Changelog</a>]</small></td> </tr> </table>"; Match m = Regex.Match(input, pattern); 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