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 = @"(?=(?=(?'a'[\s\S]*))(?<!'b'<p\b[^>][\s\S]color[\s\S]:[\s\S]black[^>][\s\S]>[\s\S]<span\b[^>][\s\S]>[\s\S])(?<!<span\b[^>][\s\S]color[\s\S]:[\s\S]black[^>][\s\S]>[\s\S])_(?=\k'a'\z)|(?<=(?=x^|(?<!&b))[\s\S]))<code\s*style=""background-color:\s*transparent;"">"; string input = @"<html> <p style=""font-family: &quot;verdana&quot;; font-size: 18px; color: black; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: cyan;""><span style=""font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;""><code style=""background-color: transparent;""><b>some text here</b></code></span></p> <span><span style=""font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;; background-color: cyan;""><code style=""background-color: transparent;""><b>some text here</b></code></span> <code style=""background-color: transparent;""> <p style=""font-family: &quot;verdana&quot;; font-size: 18px; color: cyan; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: cyan;""><span style=""color: black; font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;""><code style=""background-color: transparent;""><b>some text here</b></code></span></p> <span><span style=""font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;; background-color: cyan;""><code style=""background-color: transparent;""><b>some text here</b></code></span> <p style=""font-family: &quot;verdana&quot;; font-size: 18px; color: cyan; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: navy;""><span style=""font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;""><code style=""background-color: transparent;""><b>some text here</b></code></span></p> </html>"; 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