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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /(?P<date_time>[0-9]{4}-[0-9]{2}-[0-9]{2}\s*[0-9]{2}:[0-9]{2}:[0-9]{2}) (?P<x_edge_location>[^ ]+) (?P<sc_bytes>[0-9]+) (?P<c_ip>[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}) (?P<cs_method>[^ ]+) (?P<cs_host>[^ ]+) (?P<cs_uri_stem>[^ ]+) (?P<sc_status>[0-9]+) (?P<cs_referer>[^ ]+) (?P<cs_user_agent>[^ ]+) (?P<cs_uri_query>[^ ]+) (?P<cs_cookie>[^ ]+) (?P<x_edge_result_type>[^ ]+) (?P<x_edge_request_id>[^ ]+) (?P<x_host_header>[^ ]+) (?P<cs_protocol>[^ ]+) (?P<cs_bytes>[^ ]+) (?P<time_taken>[^ ]+) (?P<x_forwarded_for>[^ ]+) (?P<ssl_protocol>[^ ]+) (?P<ssl_cipher>[^ ]+) (?P<x_edge_response_result_type>[^ ]+) (?P<cs_protocol_version>[^ ]+) (?P<fle_status>[^ ]+) (?P<fle_encrypted_fields>[^\n]+)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?P<date_time>[0-9]{4}-[0-9]{2}-[0-9]{2}\\s*[0-9]{2}:[0-9]{2}:[0-9]{2}) (?P<x_edge_location>[^ ]+) (?P<sc_bytes>[0-9]+) (?P<c_ip>[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}) (?P<cs_method>[^ ]+) (?P<cs_host>[^ ]+) (?P<cs_uri_stem>[^ ]+) (?P<sc_status>[0-9]+) (?P<cs_referer>[^ ]+) (?P<cs_user_agent>[^ ]+) (?P<cs_uri_query>[^ ]+) (?P<cs_cookie>[^ ]+) (?P<x_edge_result_type>[^ ]+) (?P<x_edge_request_id>[^ ]+) (?P<x_host_header>[^ ]+) (?P<cs_protocol>[^ ]+) (?P<cs_bytes>[^ ]+) (?P<time_taken>[^ ]+) (?P<x_forwarded_for>[^ ]+) (?P<ssl_protocol>[^ ]+) (?P<ssl_cipher>[^ ]+) (?P<x_edge_response_result_type>[^ ]+) (?P<cs_protocol_version>[^ ]+) (?P<fle_status>[^ ]+) (?P<fle_encrypted_fields>[^\\n]+)', 'gm') const str = `---cloudFront?--- 2014-05-23 01:13:11 FRA2 182 192.0.2.10 GET d111111abcdef8.cloudfront.net /view/my/file.html 200 www.displaymyfiles.com Mozilla/4.0%20(compatible;%20MSIE%205.0b1;%20Mac_PowerPC) - zip=98101 RefreshHit MRVMF7KydIvxMWfJIglgwHQwZsbG2IhRJ07sn9AkKUFSHS9EXAMPLE== d111111abcdef8.cloudfront.net http - 0.001 - - - RefreshHit HTTP/1.1 Processed 1 2014-05-23 01:13:12 LAX1 2390282 192.0.2.202 GET d111111abcdef8.cloudfront.net /soundtrack/happy.mp3 304 www.unknownsingers.com Mozilla/4.0%20(compatible;%20MSIE%207.0;%20Windows%20NT%205.1) a=b&c=d zip=50158 Hit xGN7KWpVEmB9Dp7ctcVFQC4E-nrcOcEKS3QyAez--06dV7TEXAMPLE== d111111abcdef8.cloudfront.net http - 0.002 - - - Hit HTTP/1.1 - - `; // 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