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 = '<html><head><title>Aktuelle Werte</title><meta name=\'viewport\' content=\'width=device-width\'><style type=\'text/css\'>body{font-family:Arial;margin:0}.content{margin:10px}.r{text-align:right}td{vertical-align:top;}a{text-decoration:none;padding:10px;background:#38b5ad;color:white;display:block;width:auto;border-radius:5px;}input[type=\'text\']{width:100%;}input[type=\'password\']{width:100%;}input[type=\'submit\']{border-radius:5px;font-size:medium;padding:5px;}.submit_green{padding:9px !important;width:100%;border-style:none;background:#38b5ad;color:white;text-align:left;}</style></head><body><div style=\'min-height:120px;background-color:#38b5ad;margin-bottom:20px\'> <a href=\'/\' style=\'background:none;width:0;display:inline\'><img src=\'/images?name=luftdaten_logo\' style=\'float:left;margin:20px\'/></a> <h3 style=\'margin:0\'>Feinstaubsensor</h3> <small>ID: 2221799<br/>MAC: A0:20:A6:21:E6:XX<br/>Firmware: NRZ-2017-092</small></div><div class=\'content\'><h4>Übersicht &raquo; Aktuelle Werte</h4><table cellspacing=\'0\' border=\'1\' cellpadding=\'5\'><tr><th>Sensor</th><th>Parameter</th><th>Wert</th><tr><td colspan=\'3\'>&nbsp;</td></tr><tr><td>SDS011</td><td>PM2.5</td><td class=\'r\'>6.6&nbsp;µg/m³</td></tr><tr><td>SDS011</td><td>PM10</td><td class=\'r\'>14.6&nbsp;µg/m³</td></tr><tr><td colspan=\'3\'>&nbsp;</td></tr><tr><td>DHT22</td><td>Temperatur</td><td class=\'r\'>22.0&nbsp;°C</td></tr><tr><td>DHT22</td><td>rel. Luftfeuchte</td><td class=\'r\'>59.0&nbsp;%</td></tr><tr><td colspan=\'3\'>&nbsp;</td></tr><tr><td>WiFi</td><td>Signal</td><td class=\'r\'>-62&nbsp;dBm</td></tr><tr><td>WiFi</td><td>Qualität</td><td class=\'r\'>76&nbsp;%</td></tr></table><br/><br/><a href=\'/\' style=\'display:inline;\'>Zurück zur Startseite</a><br/><br/><br/><a href=\'http://codefor.de/\' target=\'_blank\' style=\'display:inline;background:none;width:0px;\'><img src=\'/images?name=cfg_logo\' style=\'width:200px;max-width:50%;\'/></a></div></body></html>'; my $regex = qr/(?:PM10<\/td><td class='r'>)(\d+.\d)/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