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

/
/
g

Test String

Code Generator

Language

Generated Code

use strict; my $str = '//Version 1.0 Aug 31st 2011 -First Release. //Version 1.1 Sep 29th 2011 //Bug fixed: When using hovercard in hovercard, the inner hovercard shows up as well when parent hovercard opens. // //Version 1.2 Sep 30th 2011 //Enhancement: The hovercard now adjust (either open on left or right) in accordance to the view port. //Added options: //openOnLeft: force hovercard to open on left. (eg: if the hovered name appear in the end of sentence) // //Version 2.0 Nov 8th 2011 //Bug Fixes: zindex issue. //Enhancements: Supercool built in social profile cards like Twitter and Facebook! //Added options: //showTwitterCard: displays a built in twitter card format for a twitter screenname. Maximum 150 twitter lookup per hour. //twitterScreenName: twitter screen name for the hovercard. If no username/screenname is provided, hovercard attempts to look up for hovered text. //showFacebookCard: displays a built in facebook card format for a facebook username/pages/events etc. Works best with Facebook pages. //facebookUserName: facebook username/pages/events/groups for the hovercard. If no username is provided, hovercard attempts to look up for hovered text. // //Version 2.1 Nov 22nd 2011 //Enhancement: attribute \'data-hovercard\'. You may now use data-hovercard attribute with your label/link etc to set the twitter or facebook usernames. //Added options: //showCustomCard: You may now add your own custom data source and display the profile data using existing card format. // //Version 2.2 Dec 9th 2011 //Bug Fixes: zindex issue with IE7. // //Version 2.3 Dec 15th 2011 //Enhancement: The plugin now auto adjust on the edges of visible window/viewport! //Added options: //openOnTop: Set \'openOnTop\' to true if you want the hovercard to always open on left. //customCardJSON: Provide a local json data with showCustomCard. Inherits plugin\'s social card format/styles. //delay: Delay the hovercard appearance on hover. // //Version 2.4 Apr 12th 2012 //Added options: //autoAdjust: The plugin\'s default functionality to auto adjust to the viewport '; my $regex = qr/.*Version (\S+)/p; if ( $str =~ /$regex/g ) { 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