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
  • A character except: a, b or c
  • A character in the range: a-z
  • A character not in the range: a-z
  • A character in the range: a-z or A-Z
  • Any single character
  • Alternate - match either a or b
  • Any whitespace character
  • Any non-whitespace character
  • Any digit
  • Any non-digit
  • Any word character
  • Any non-word character
  • Match everything enclosed
  • Capture everything enclosed
  • Zero or one of a
  • Zero or more of a
  • One or more of a
  • Exactly 3 of a
  • 3 or more of a
  • Between 3 and 6 of a
  • Start of string
  • End of string
  • A word boundary
  • Non-word boundary

Regular Expression
No Match


Test String

Code Generator

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^[a-z][a-z0-9]*(([A-Z]{1,3}[a-z0-9]+)*[A-Z]{0,3}|([a-z0-9]+[A-Z]{1,3})*|[A-Z]{1,3})$"; string input = @"snake_case PascalCase 2PascalCase streamIOIO gREATERDtha modeADFAFdsADFads aBabcABCDabcABC camelCa_1 contextHTMLParser hELLO modeADFdsADFads streamIO aBCabcABCabcA aBCabcA aabc123 aabcABC ab abc abcd abcde deviceSNS pathASNs dscpCP awsVPC deviceID camelCasecamelCasecamelCasecamelCasecamelCasecamelCase gREA1 gREAt gREAtREAt cP3 a1 aABC a123 modeADFsADFads a1G aG a modeADFads camelCase lThan30DaysCount lessThan30DaysCount lessThan30DaysCountA greaterThan30LessThan60DaysCount greaterThan60LessThan90DaysCount greaterThan90DaysCount pascalCase pascal2Case pascalCaseA pascal2CaseA modeA mode2A mode2A2 mode2A2A createAMode createBMode madeEasy wonderFul andMe htmlParser h aaA camel01C camel01c01 camel01C01 camel01CC01 camel0a1c1 camel0a1C1 camel0ac1b1C1 camelC camelC1 camelCA camelCa1 ibsReleaseTestVerificationRegressionSuite ibsReleaseTestVerificationRegressioNSuite ibsReleaseTestVerificationRegressioN xmlHttpRequest newCustomerId innerStopwatch supportsIpv6OnIos youTubeImporter youtubeImporter affine3D"; 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: