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

r"
"
g

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('(?<=\\s|\\A)([^\\s=]+)=(.*?)(?=(?:\\s[^\\s=]+=|$))', 'g') const str = `eventId=588622 app=HTTP in=5326 out=5326 categorySignificance=/Normal categoryBehavior=/Communicate/Query categoryDeviceGroup=/Application catdt=Web Cache categoryOutcome=/Success categoryObject=/Host/Application/Service art=1359127995713 cat=Access Log deviceSeverity=2 rt=1359127975000 src=1.1.1.1 sourceZoneURI=/All Zones/ArcSight System/Public Address Space Zones/US Department of Defense dst=208.85.40.20 destinationZoneURI=/All Zones/ArcSight System/Public Address Space Zones/ARIN/204.0.0.0-209.255.255.255 (ARIN) dpt=80 fileType=application/json; request=http://www.pandora.com/json/music/artist/justin-moore?explicit\\=false requestMethod=GET requestClientApplication=Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.142 Safari/535.19 cs2=false cs3=http://www.pandora.com/ cs5=Default cs1Label=Virus Name cs2Label=AV Enabled cs3Label=Referrer cs4Label=URL Category cs5Label=Policy cs6Label=Reputation ahost=ndeusemslvarc04.gold.rtgold.nima.mil agt=214.28.240.186 agentZoneURI=/All Zones/ArcSight System/Public Address Space Zones/US Department of Defense av=5.2.7.6474.0 atz=GMT aid=3DLoiRDsBABCAA9FvE1htRg\\=\\= at=syslog dvchost=xxx-xxx-xxx dtz=GMT _cefVer=0.1 ad.charset=utf-8`; // 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