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

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?:[a-zA-Z\s]*:)\s*(.*)"; string input = @"Type : Requirement State : Implemented Release : 3.1.9 / 3.4.0 *1 The AFTN Message processing shall base on the following external documents: [ICAO_1] ICAO Annex 10 [ICAO_2] ICAO Doc 4444 [ICAO_3] ICAO Doc 7030 [ICAO_4] ICAO Doc 4444 PANS ATM Amendment No1 *1 [EURO_1] ADEXP documentation [EURO_2] IFPS user manual [CFMU_1] CFMU_AIC 12.08 [CFMU_2] CFMU 2012 REQUIREMENTS V1.42 *1 [CFMU_3] CFMU INTERFACE MANUAL FOR ICAO 2012 V1.32 *1 [AIDA_1] ICD FPL AIDA AFPS v40 [FIXM_1] http://www.fixm.aero/content/fixm-core-releases (FIXM v1.1) *1 Due to mutually contradictory between ICAO and CFMU requirements, the documents from CFMU has a higher priority."; RegexOptions options = RegexOptions.Multiline; foreach (Match m in Regex.Matches(input, pattern, options)) { 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