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

/
/

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?<req_ip>[\d\.]+)\s(?<req_unk1>[\w\-]+)\s(?<req_unk2>[\w\-]+)\s\[(?<req_ts>\d+\/\w+\/\d+\:\d+\:\d+\:\d+\s\+\d+)\]\s\""(?<req_full>.+?)\""\s(?<req_status>[\d\-]+)\s(?<req_bytes_in>[\d\-]+)\s\""(?<req_referrer>.+?)\""\s\""(?<req_ua>.+?)\""\s\""(?<req_cookie>.+?)\""\s\""(?<req_waf_info>.+?)\""\s\""(?<req_customfield>.+?)\"""; string input = @"1.1.1.1 - - [05/May/2015:13:23:13 +0000] ""HEAD /www.arl.com/path/to/file.php HTTP/1.1"" 200 265 ""-"" ""Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"" ""-"" ""-"" ""UNKNOWN"""; Match m = Regex.Match(input, pattern); Console.WriteLine("'{0}' found at index {1}", m.Value, m.Index); } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx