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 = /(?P<browser>Android|Ios|Windows)\s(?P<major_version>\d+)\.(?P<minor_version>\d+\.?\d?);(?P<lang>\spt-br|\seng|\sita|\sesp|\sjap|\srus|\skor|\sch){0,1};{0,1}(?P<device>[ \w\-?]+)\s/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?P<browser>Android|Ios|Windows)\\s(?P<major_version>\\d+)\\.(?P<minor_version>\\d+\\.?\\d?);(?P<lang>\\spt-br|\\seng|\\sita|\\sesp|\\sjap|\\srus|\\skor|\\sch){0,1};{0,1}(?P<device>[ \\w\\-?]+)\\s', 'g') const str = `20-03-2017 17:26:39 GET /ourapps.php HTTP/1.1 HTTP headers: Accept-Language: pt-BR,en-US;q=0.8 Accept-Encoding: gzip, deflate User-Agent: Mozilla/5.0 (Linux; Android 5.1; 4017F Build/LMY47I; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/43.0.2357.121 Mobile Safari/537.36 Accept: application/json, text/plain, */* Connection: close 20-03-2017 20:17:08 GET /ourapps.php HTTP/1.1 HTTP headers: Accept-Charset: utf-8, iso-8859-1, utf-16, *;q=0.7 Accept-Language: pt-BR, en-US Accept-Encoding: gzip,deflate X-Wap-Profile: http://gsm.lge.com/html/gsm/E467f-M3-D1.xml User-Agent: Mozilla/5.0 (Linux; U; Android 4.1.2; pt-br; LG-E467f Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 Accept: application/json, text/plain, */* Connection: close 20-03-2017 21:09:36 GET /ourapps.php HTTP/1.1 HTTP headers: Accept-Language: pt-BR,en-US;q=0.8 Accept-Encoding: gzip,deflate User-Agent: Mozilla/5.0 (Linux; Android 4.4.2; eng; SM-G355M Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/30.0.0.0 Mobile Safari/537.36 Accept: application/json, text/plain, */* Connection: close `; // 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