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

r"""
"""
g

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"<a.*href.?=.?[""'](?:\b\w+://)?([\w-]+(?:\.[\w-]+)+)[/:?]?.*?[""'].*?>?(?:</)?.?>"; string input = @"<a href=""http://stepic.org/courses""> <a href='https://stepic.org'> <a href='http://neerc.ifmo.ru:1345'> <a href=""ftp://mail.ru/distib"" > <a href=""ya.ru""> <a href=""www.ya.ru""> <a href=""../skip_relative_links""> <a target=""blank"" href='http://sas-_0123d.ifmo.ru:1345'> <a href='http://neerc.ifmo.ru:1345'> <a href=""../some_path/index.html""> <a href=""https://www.ya.ru""> <a href=""ftp://mail.ru/distib"" > <a href=""bya.ru""> <a href=""http://www.ya.ru""> <a href=""www.kya.ru""> <a href=""../skip_relative_links""> <a href=""http://stepic.org/courses""> <a class = ""hello"" href= ""http://ftepic.org/courses"" id=""dfdf""> <p class = ""hello"" href= ""http://dtepic.org/courses""> <a class = ""hello"" href = ""http://a.b.vc.ttepic.org/courses""> <a href='https://stepic.org'> <a href='http://neerc.ifmo.ru:1345' > <a href = ""ftp://mail.ru/distib"" > <a href= ""ya.ru""> <a href =""www.ya.ru""> <a href=""../skip_relative_links""> <link rel=""image_src"" href=""https://examaple.org/files/6a2/72d/e09/6a272de0944f447fb5972c44cc02f795.png"" /> <a href=""http://www.gtu.edu.ge/index_e.htm"" target=""_top"">Georgian Technical University</a> <a href=""http://stepic-2.org/courses""> <a href=""ftp://www.mya-2.ru""> <a href='https://stepic-2.org'> <a link href='http://neerc.ifmo-2.ru:1345'> <a title=test download=""http://test.com""; href=""test.com"" class=""my test"" style=> <a title=test class=""my test"" href= ""test1.com:8080/test/path?get=http://test2.ru/?true""; rel=""nofollow"" style=> <a title=test meta=""whatever http://test1.com""; href = ""test.com?get=http://test2.ru/?true""; class=""my test"" style= > <a target=""blank"" href='http://sasd.ifmo-2.ru:1345'> <a href='http://neerc.ifmo-2.ru:1345'> <a href=""../some_path/index-2.html""> <a href=""https://www.ya-2.ru""> <a href=""ftp://mail-2.ru/distib"" > <a href=""bya-2.ru""> <a href=""http://www.ya-2.ru""> <a href=""www.kya-2.ru"" > <a href=""../skip_relative_links-2""> <a href=""http://stepic-2.org/courses""> <a class = ""hello-2"" href= ""http://ftepic-2.org/courses"" id=""dfdf""> <p class = ""hello-2"" href= ""http://dtepic-2.org/courses""> <a class = ""hello-2"" href = ""http://a.b.vc.ttepic-2.org/courses""> <a href='https://stepic-2.org'> <a href='http://neerc.ifmo-2.ru:1345' > <a href = ""ftp://mail-2.ru/distib"" > <a href= ""ya-2.ru""> <a href =""www.ya-2.ru""> <a href=""../skip_relative_links""> <link rel=""image_src"" href=""https://examaple.org/files/6a2/72d/e09/6a272de0944f447fb5972c44cc02f795.png"" /> <a href=""http://www.gtu.edu-2.ge/index_e.htm"" target=""_top"">Georgian Technical University</a> <a class-8 = ""hello-2"" href= ""http://zzz.last.test-1.stepic.org/courses"" id=""dfdf""> <a class-4-4 = ""hello-2-raz"" href = ""http://zzz.last.test-2.stepic.org/courses"" > <a href =""https://stepic.org/media/attachments/lesson/24471/02"">"; foreach (Match m in Regex.Matches(input, pattern)) { 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