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"
"
xsm

Test String

Code Generator

Language

Generated Code

use strict; my $str = 'Message-ID: <3490571.1075846143093.JavaMail.evans@thyme> Date: Wed, 8 Sep 1999 08:50:00 -0700 (PDT) From: steven.kean@enron.com To: kelly.kimberly@enron.com Subject: Re: India And The WTO Services Negotiation Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-From: Steven J Kean X-To: Kelly Kimberly X-cc: X-bcc: X-Folder: \\Steven_Kean_Dec2000_1\\Notes Folders\\All documents X-Origin: KEAN-S X-FileName: skean.nsf fyi ---------------------- Forwarded by Steven J Kean/HOU/EES on 09/08/99 03:49 PM --------------------------- Joe Hillings@ENRON 09/08/99 02:52 PM To: Joe Hillings/Corp/Enron@Enron cc: Sanjay Bhatnagar/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Terence H Thorn/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Ashok Mehta/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, John Ambler/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Steven J Kean/HOU/EES@EES, Jeffrey Sherrick/Corp/Enron@Enron Subject: Re: India And The WTO Services Negotiation Sanjay: Some information of possible interest to you. I attended a meeting this afternoon of the Coalition of Service Industries, one of the lead groups promoting a wide range of services including energy services in the upcoming WTO GATTS 2000 negotiations. CSI President Bob Vastine was in Delhi last week and met with CII to discuss the upcoming WTO. CII apparently has a committee looking into the WTO. Bob says that he told them that energy services was among the CSI recommendations and he recalls that CII said that they too have an interest. Since returning from the meeting I spoke with Kiran Pastricha and told her the above. She actually arranged the meeting in Delhi. She asked that I send her the packet of materials we distributed last week in Brussels and London. One of her associates is leaving for India tomorrow and will take one of these items to Delhi. Joe Joe Hillings 09/08/99 11:57 AM To: Sanjay Bhatnagar/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT cc: Terence H Thorn/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Ashok Mehta/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, John Ambler/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Steven J Kean/HOU/EES@EES, Jeffrey Sherrick/Corp/Enron@Enron (bcc: Joe Hillings/Corp/Enron) Subject: India And The WTO Services Negotiation Sanjay: First some information and then a request for your advice and involvment.'; my $regex = qr/^Date:\ (?P<date>.+?$) .+? ^From:\ (?P<sender>.+?$) .+? ^To:\ (?P<to>.+?$) .+? ^cc:\ (?P<cc>.+?$) .+? ^Subject:\ (?P<subject>.+?$)/xsmp; 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