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

/
/

Test String

Code Generator

Language

Generated Code

use strict; my $str = '<font size=\'1\'><table class=\'xdebug-error xe-notice\' dir=\'ltr\' border=\'1\' cellspacing=\'0\' cellpadding=\'1\'> <tr><th align=\'left\' bgcolor=\'#f57900\' colspan="5"><span style=\'background-color: #cc0000; color: #fce94f; font-size: x-large;\'>( ! )</span> Notice: Undefined index: in C:\\wamp\\www\\form.php on line <i>464</i></th></tr> <tr><th align=\'left\' bgcolor=\'#e9b96e\' colspan=\'5\'>Call Stack</th></tr> <tr><th align=\'center\' bgcolor=\'#eeeeec\'>#</th><th align=\'left\' bgcolor=\'#eeeeec\'>Time</th><th align=\'left\' bgcolor=\'#eeeeec\'>Memory</th><th align=\'left\' bgcolor=\'#eeeeec\'>Function</th><th align=\'left\' bgcolor=\'#eeeeec\'>Location</th></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>1</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.0008</td><td bgcolor=\'#eeeeec\' align=\'right\'>274560</td><td bgcolor=\'#eeeeec\'>{main}( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>2</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8826</td><td bgcolor=\'#eeeeec\' align=\'right\'>38298888</td><td bgcolor=\'#eeeeec\'>do_action( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>3</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300392</td><td bgcolor=\'#eeeeec\'><a href=\'http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}\' target=\'_new\'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>4</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300560</td><td bgcolor=\'#eeeeec\'>Example_Post->ajax_Example_posting_form( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>5</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38301552</td><td bgcolor=\'#eeeeec\'>Example_Post->Example_form_submitting( )</td><td title=\'C:\\wamp\\www\\form.php\' bgcolor=\'#eeeeec\'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font> <br /> <font size=\'1\'><table class=\'xdebug-error xe-notice\' dir=\'ltr\' border=\'1\' cellspacing=\'0\' cellpadding=\'1\'> <tr><th align=\'left\' bgcolor=\'#f57900\' colspan="5"><span style=\'background-color: #cc0000; color: #fce94f; font-size: x-large;\'>( ! )</span> Notice: Undefined index: name in C:\\wamp\\www\\form.php on line <i>475</i></th></tr> <tr><th align=\'left\' bgcolor=\'#e9b96e\' colspan=\'5\'>Call Stack</th></tr> <tr><th align=\'center\' bgcolor=\'#eeeeec\'>#</th><th align=\'left\' bgcolor=\'#eeeeec\'>Time</th><th align=\'left\' bgcolor=\'#eeeeec\'>Memory</th><th align=\'left\' bgcolor=\'#eeeeec\'>Function</th><th align=\'left\' bgcolor=\'#eeeeec\'>Location</th></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>1</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.0008</td><td bgcolor=\'#eeeeec\' align=\'right\'>274560</td><td bgcolor=\'#eeeeec\'>{main}( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>2</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8826</td><td bgcolor=\'#eeeeec\' align=\'right\'>38298888</td><td bgcolor=\'#eeeeec\'>do_action( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>3</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300392</td><td bgcolor=\'#eeeeec\'><a href=\'http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}\' target=\'_new\'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>4</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300560</td><td bgcolor=\'#eeeeec\'>Example_Post->ajax_Example_posting_form( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>5</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38301552</td><td bgcolor=\'#eeeeec\'>Example_Post->Example_form_submitting( )</td><td title=\'C:\\wamp\\www\\form.php\' bgcolor=\'#eeeeec\'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font> {"redirect_to":"false","show_message":true,"message":"<div class=\\"notification alert-success\\"><p>Post updated successfully<\\/p><a href=\\"#\\" class=\\"close-btn\\">\\u00d7<\\/a><\\/div><br \\/>"} <font size=\'1\'><table class=\'xdebug-error xe-notice\' dir=\'ltr\' border=\'1\' cellspacing=\'0\' cellpadding=\'1\'> <tr><th align=\'left\' bgcolor=\'#f57900\' colspan="5"><span style=\'background-color: #cc0000; color: #fce94f; font-size: x-large;\'>( ! )</span> Notice: Undefined index: in C:\\wamp\\www\\form.php on line <i>464</i></th></tr> <tr><th align=\'left\' bgcolor=\'#e9b96e\' colspan=\'5\'>Call Stack</th></tr> <tr><th align=\'center\' bgcolor=\'#eeeeec\'>#</th><th align=\'left\' bgcolor=\'#eeeeec\'>Time</th><th align=\'left\' bgcolor=\'#eeeeec\'>Memory</th><th align=\'left\' bgcolor=\'#eeeeec\'>Function</th><th align=\'left\' bgcolor=\'#eeeeec\'>Location</th></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>1</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.0008</td><td bgcolor=\'#eeeeec\' align=\'right\'>274560</td><td bgcolor=\'#eeeeec\'>{main}( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>0</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>2</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8826</td><td bgcolor=\'#eeeeec\' align=\'right\'>38298888</td><td bgcolor=\'#eeeeec\'>do_action( )</td><td title=\'C:\\wamp\\www\\Example\\wp-admin\\admin-ajax.php\' bgcolor=\'#eeeeec\'>..\\admin-ajax.php<b>:</b>85</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>3</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300392</td><td bgcolor=\'#eeeeec\'><a href=\'http://www.php.net/function.call-user-func-array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}\' target=\'_new\'>call_user_func_array:{C:\\wamp\\www\\Example\\wp-includes\\plugin.php:505}</a> ( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>4</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38300560</td><td bgcolor=\'#eeeeec\'>Example_Post->ajax_Example_posting_form( )</td><td title=\'C:\\wamp\\www\\Example\\wp-includes\\plugin.php\' bgcolor=\'#eeeeec\'>..\\plugin.php<b>:</b>505</td></tr> <tr><td bgcolor=\'#eeeeec\' align=\'center\'>5</td><td bgcolor=\'#eeeeec\' align=\'center\'>0.8827</td><td bgcolor=\'#eeeeec\' align=\'right\'>38301552</td><td bgcolor=\'#eeeeec\'>Example_Post->Example_form_submitting( )</td><td title=\'C:\\wamp\\www\\form.php\' bgcolor=\'#eeeeec\'>..\\Example-frontend-form.php<b>:</b>116</td></tr> </table></font>'; my $regex = qr/(\{\".*?:.*?\"\})/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