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

const regex = /(?:PM10<\/td><td class='r'>)(\d+.\d)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?:PM10<\\\/td><td class=\'r\'>)(\\d+.\\d)', 'g') const 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>`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions