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 = /Level>(\d+)<\/tank/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('Level>(\\d+)<\\\/tank', 'g') const str = `This XML file does not appear to have any style information associated with it. The document tree is shown below. <seqSmartbox xmlns="http://tecson.dev.oilview.de/gateway/xsd" xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance" xsi:schemaLocation="http://tecson.dev.oilview.de/gateway/xsd/smartbox.xsd"> <seqHeader> <indication>Manuelle Abfrage</indication> <authCode>03B41236A899</authCode> <devOperator/> <devLocation/> <devID>2-852</devID> <devVersion>V6.02</devVersion> </seqHeader> <seqData> <seqTanks> <tankNumber>1</tankNumber> <tankName>Heizöl</tankName> <seqTankLevel> <tankLevel>490</tankLevel> <tankUnit>L</tankUnit> </seqTankLevel> <tankPercent>5</tankPercent> <seqTankSize> <tankSize>10000</tankSize> <tankUnit>L</tankUnit> </seqTankSize> <seqTankClear> <tankClearance>9010</tankClearance> <tankUnit>L</tankUnit> </seqTankClear> </seqTanks> </seqData> <seqPara> <para1>30</para1> <para2>15</para2> <para4>0</para4> <para5>5</para5> <para9>0</para9> </seqPara> </seqSmartbox>`; // 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