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

use strict; my $str = ' <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>'; my $regex = qr/<th(?:| | .*?)>\s*<a(?:| | .*?)>\s*([\d.]+)\s*</a>\s*</th>\s*<td(?:| | .*?)>\s*stable\s*</td>/p; if ( $str =~ /$regex/ ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html