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 = @"(?:\""(?:(?<=\""(?=[^\n]))[^\n]+?(?=(?<!\\))(?=\""))?\"")|(\B'(?:(?<='(?=[^\n]))[^\n]+?(?=(?<!\\))(?='))?')"; string input = @" 1. Valid double-quoted strings: - ""Hello"" - ""This is a test"" - ""123"" - ""Special characters: @#$%^&*()_+"" - ""Escape sequence: \n"" 2. Valid double-quoted strings with additional characters or variables: - "" test aaaaa \"" "" + asdf - "" test "" + ( ""aaaaa"" ) + gdf - "" test \"" "" + `"" aaaa "" + dfg - "" test ' aaaaa \"" "" + dfg - "" 3. Valid double-quoted strings with special characters: - ""sas''as\""a1\'2 ! -_?:sa"" - ""''"" - ""\abnb\ajhgf\crt098& \""'"" 4. Invalid double-quoted strings: - "" test "" + ( ""aaaaa"" ) \"" saf - ""\\ + \* test "" \$ \. dsdfs - (\"" test \"" "" + "" aaaa "" sfgd - ' test ' + aas ( ""aaaaa"" ) + '\ sd - '\\ + \* test ' \$ \. trace - (' test ' as ' + ' aaaa ' - '""' - '""sas' - 'ads' - 'asdasd\""asdsa' - ""klkl""klkl - ""asa\'sasa\\"" - \'\\\' - ""hhhh""klkl"" - 'jkjkjk'klklk' - '\""\\\""' - '' - '\""asa\'sasa\\\""' - ""sasasasa\\\\\\"" 1. Valid single-quoted strings: - 'Hello' - 'This is a test' - '123' - 'Special characters: @#$%^&*()_+' - 'Escape sequence: \n' 2. Valid single-quoted strings with additional characters or variables: - ' test aaaaa \' ' + asdf - ' test ' + ( 'aaaaa' ) + gdf - ' test \' ' + ' aaaa' + dfg - ' test "" aaaaa \' ' + dfg - '' 3. Valid single-quoted strings with special characters: - 'sas""as\'a1\""2 ! -_?:sa' - '""' - '\abnb\ajhgf\crt098& \'""' 4. Invalid single-quoted strings: - ' test ' + ( 'aaaaa' ) \' saf - '\\ + \* test ' \$ \. dsdfs - (\' test \' + ' aaaa ' sfgd - "" test \"" "" + "" aaaa "" sfgd - ' test ' + aas ( 'aaaaa' ) + '\ sd - '\\ + \* test ' \$ \. trace - (' test ' as ' + ' aaaa ' - ""''"" - 'sas"" - ""ads' - 'asdasd\'asdsa' - ""klkl""klkl - ""asa\'sasa\\"" - \'\\\' - 'hhhh""klkl\'\ - \'jkjkjk""klklk' - ""\'\\\'"" - '' - '\""asa\'sasa\\\""' - 'sasasasa\\\\\\' "; 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