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

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^(=?202\d)(\d{0,3}[A-Z]{1,4}|[A-Z]{1,4}\d{1,3})([\dA-Z]{0,4})A"; string input = @"Matches R1 R2 R3 R4 R5 R6 2022A144A OK OK OK OK \D\d\d\d 20228BC3A OK OK OK OK \d\D\D\d 20228Z1DA OK OK OK OK \d\D\d\D 2022K2 A 20229999A NOK \d\d\d\d 2022B123A OK OK OK OK \D\d\d\d 20221B23A OK OK OK OK \d\D\d\d 202212B3A NOK NOK NOK OK OK \d\d\D\d 2022123BA NOK OK \d\d\d\D 2022ABCDA 2022K2 A Matches 100% as desired R 12 2022(\d\D\w\w|\D\d\w\w|\d\d\D\w|\d\d\w\D|\D\D\D\D)A R 13 ^(=?202\d)(\d{0,3}[A-Z]{1,4}|[A-Z]{1,4}\d{1,3})([\dA-Z]{0,4})A Should match R1: 2022\d\D\w\wA R2: 2022\D\d\w\wA R3: 2022(\d\D\w\w|\D\d\w\w)A R4: 2022(\d\D\w\w|\D\d\w\w|\d\d\D\w)A R5: 2022(\d\D\w\w|\D\d\w\w|\d\d\D\w|\d\d\w\D)A R 10 ^(=?202\d)(\d*[A-Z]|[A-Z]*)([\dA-Z]{1,3})A R 11 ^(=?202\d)(\d{1,3}[A-Z]*)([\dA-Z]{1,3})A R 12 ^(=?202\d)(\d{1,3}[A-Z]{1,3}|[A-Z]{1,3}\d{1,3})([\dA-Z]{0,3})A ^ Start of string (?=[a-z\d]{8,}$) Positive lookahead, assert 8 or more chars a-z or digits till end of string (?=\d*[a-z]) Positive lookahead to assert at least a char a-z [a-z]* Match optional chars a-z \d Match at least a single digit [a-z\d]* Match optional chars a-z or digits $ End of string Should not match R6: 2022([A-Z0-9]{1,4})A R7: 2022(\d|\w){1,3}\wA <-- also matches 20229999A which it should not R8: 2022\w\w\s\sA R9 2022\d\d\d\dA"; 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