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 = '<!DOCTYPE html> <html dir="ltr" lang="en" xml:lang="en"> <div id="page" class="container-fluid clearfix"> <div id="page-content" class="row-fluid"> <div id="region-bs-main-and-pre" class="span9"> <div class="row-fluid"> <section id="region-main" class="span8 pull-right"> <div role="main"><span id="maincontent"></span><div class="no-overflow"><table cellspacing="0" id="overview-grade" class="flexible boxaligncenter generaltable"><thead><tr><th class="header c0" scope="col">Course name<div class="commands"></div></th><th class="header c1" scope="col">Grade<div class="commands"></div></th></tr></thead><tbody><tr class="" id="grade-report-overview-45567_r0"><td class="cell c0" id="grade-report-overview-45567_r0_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=723&amp;user=45567">[BIOL 107 Section 1] Concepts in Biology</a></td><td class="cell c1" id="grade-report-overview-45567_r0_c1">-</td></tr><tr class="" id="grade-report-overview-45567_r1"><td class="cell c0" id="grade-report-overview-45567_r1_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=5153&amp;user=45567">[CENG 230 All Sections] Introduction to C Programming</a></td><td class="cell c1" id="grade-report-overview-45567_r1_c1">-</td></tr><tr class="" id="grade-report-overview-45567_r2"><td class="cell c0" id="grade-report-overview-45567_r2_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=3054&amp;user=45567">[CENG 230 Section 7] Introduction to C Programming</a></td><td class="cell c1" id="grade-report-overview-45567_r2_c1">-</td></tr><tr class="" id="grade-report-overview-45567_r3"><td class="cell c0" id="grade-report-overview-45567_r3_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=3538&amp;user=45567">[ENG 101 Section 40] English for Academic Purposes I</a></td><td class="cell c1" id="grade-report-overview-45567_r3_c1">37.25</td></tr><tr class="" id="grade-report-overview-45567_r4"><td class="cell c0" id="grade-report-overview-45567_r4_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=3208&amp;user=45567">[FDE 101 Section 1] Introduction to Food Engineering</a></td><td class="cell c1" id="grade-report-overview-45567_r4_c1">55.33</td></tr><tr class="" id="grade-report-overview-45567_r5"><td class="cell c0" id="grade-report-overview-45567_r5_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=5358&amp;user=45567">[MATH 119 All Sections] Calculus with Analytic Geometry</a></td><td class="cell c1" id="grade-report-overview-45567_r5_c1">-</td></tr><tr class="" id="grade-report-overview-45567_r6"><td class="cell c0" id="grade-report-overview-45567_r6_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=578&amp;user=45567">[MATH 119 Section 15] Calculus with Analytic Geometry</a></td><td class="cell c1" id="grade-report-overview-45567_r6_c1">-</td></tr><tr class="" id="grade-report-overview-45567_r7"><td class="cell c0" id="grade-report-overview-45567_r7_c0"><a href="https://odtuclass.metu.edu.tr/course/user.php?mode=grade&amp;id=219&amp;user=45567">[PHYS 105 Section 16] General Physics I</a></td><td class="cell c1" id="grade-report-overview-45567_r7_c1">-</td></tr><h3>Courses I am taking</h3><br /><tr class="emptyrow" id="grade-report-overview-45567_r8"><td class="cell c0" id="grade-report-overview-45567_r8_c0"></td><td class="cell c1" id="grade-report-overview-45567_r8_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r9"><td class="cell c0" id="grade-report-overview-45567_r9_c0"></td><td class="cell c1" id="grade-report-overview-45567_r9_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r10"><td class="cell c0" id="grade-report-overview-45567_r10_c0"></td><td class="cell c1" id="grade-report-overview-45567_r10_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r11"><td class="cell c0" id="grade-report-overview-45567_r11_c0"></td><td class="cell c1" id="grade-report-overview-45567_r11_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r12"><td class="cell c0" id="grade-report-overview-45567_r12_c0"></td><td class="cell c1" id="grade-report-overview-45567_r12_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r13"><td class="cell c0" id="grade-report-overview-45567_r13_c0"></td><td class="cell c1" id="grade-report-overview-45567_r13_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r14"><td class="cell c0" id="grade-report-overview-45567_r14_c0"></td><td class="cell c1" id="grade-report-overview-45567_r14_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r15"><td class="cell c0" id="grade-report-overview-45567_r15_c0"></td><td class="cell c1" id="grade-report-overview-45567_r15_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r16"><td class="cell c0" id="grade-report-overview-45567_r16_c0"></td><td class="cell c1" id="grade-report-overview-45567_r16_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r17"><td class="cell c0" id="grade-report-overview-45567_r17_c0"></td><td class="cell c1" id="grade-report-overview-45567_r17_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r18"><td class="cell c0" id="grade-report-overview-45567_r18_c0"></td><td class="cell c1" id="grade-report-overview-45567_r18_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r19"><td class="cell c0" id="grade-report-overview-45567_r19_c0"></td><td class="cell c1" id="grade-report-overview-45567_r19_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r20"><td class="cell c0" id="grade-report-overview-45567_r20_c0"></td><td class="cell c1" id="grade-report-overview-45567_r20_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r21"><td class="cell c0" id="grade-report-overview-45567_r21_c0"></td><td class="cell c1" id="grade-report-overview-45567_r21_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r22"><td class="cell c0" id="grade-report-overview-45567_r22_c0"></td><td class="cell c1" id="grade-report-overview-45567_r22_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r23"><td class="cell c0" id="grade-report-overview-45567_r23_c0"></td><td class="cell c1" id="grade-report-overview-45567_r23_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r24"><td class="cell c0" id="grade-report-overview-45567_r24_c0"></td><td class="cell c1" id="grade-report-overview-45567_r24_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r25"><td class="cell c0" id="grade-report-overview-45567_r25_c0"></td><td class="cell c1" id="grade-report-overview-45567_r25_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r26"><td class="cell c0" id="grade-report-overview-45567_r26_c0"></td><td class="cell c1" id="grade-report-overview-45567_r26_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r27"><td class="cell c0" id="grade-report-overview-45567_r27_c0"></td><td class="cell c1" id="grade-report-overview-45567_r27_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r28"><td class="cell c0" id="grade-report-overview-45567_r28_c0"></td><td class="cell c1" id="grade-report-overview-45567_r28_c1"></td></tr><tr class="emptyrow" id="grade-report-overview-45567_r29"><td class="cell c0" id="grade-report-overview-45567_r29_c0"></td><td class="cell c1" id="grade-report-overview-45567_r29_c1"></td></tr></tbody></table></div></div> </section> </div> </div> </div> </div> </body> </html> '; my $regex = qr/<a\s*[^>]*?>(?![^<]*?All).*?<\/a>/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