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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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

"
"
mg

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^(?<scheme>[a-zA-Z][a-zA-Z0-9-+.]*)://(?:(?<username>(?:[\w-]|%\d\d)+)(?::(?<passwd>(?:[\w-]|%\d\d)*))?@)?(?<host>(?:[a-zA-Z][a-zA-Z0-9-]*\.?)+|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})(?<port>:\d+)?(?<path>(?:/(?:[\w-.:]|%\d\d)+)+/?|/)?(?<query>\?(?:(?:[\w-]|%\d\d)+(?:=[\w]+)?(?:&|$))*)?(?<fragment>#.*)?$"; string input = @"https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#Syntax (↑ assuming URL, not URI; the only difference is that the host is mandatory) https://regex101.com/ https://e./ https://org. https://elearning.tgm.ac.at/pluginfile.php/297744/mod_resource/content/0/SEW5_UML_Einfuehrung.pdf https://elearning.tgm.ac.at/mod/page/view.php?id%40_-ae=212356 https://elearning.tgm.ac.at/mod/assign/view.php?id=212239 https://elearning.tgm.ac.at/course/view.php?id=5454&section=4 nonstandardscheme://is.still.valid http://he.e/? https://hy.a?a http://h.?a&b&c=a https://e.o.a. http://0riedler:0%20tab-a_sco@riedler.a.wien/ http://emptypasswd:@riedler.wien/ http://a.e:33/ https://de.wikipedia.org/wiki/Wikipedia:Hauptseite https://de.wikipedia.org/wiki/Preiselbeersauce#Zubereitung https://toptoptoptoptoptoptoptoptoptoptoptoptoptoptoptoptoptoptoptop.top/ https://9.9.9.9/ipv4 https://2620:fe::fe/ipv6 ipv6 addresses are their own source of evil, not implementing those for now"; 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