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

/
/
g

Test String

Substitution

Processing...

Code Generator

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"\s*<script src=""\/((\w+)[\w.\/]+)""><\/script>"; string substitution = @"\n<script>\n const $2Script = document.createElement('script');\n $2Script.type = 'text/javascript';\n $2Script.async = true;\n $2Script.src = '$1';\n document.body.appendChild($2Script);\n</script>\n"; string input = @"<!DOCTYPE html> <html> <head> <meta charset=""utf-8""> <meta http-equiv=""Content-Security-Policy"" content=""default-src * data: gap: https://ssl.gstatic.com; style-src * 'unsafe-inline'; script-src * 'unsafe-inline' 'unsafe-eval'""> <meta name=""viewport"" content=""width=device-width,initial-scale=1.0""> <title>atomic-project</title> </head> <body> <div id=""app""></div> <!-- built files will be auto injected --> <script src=""/app.js""></script><script src=""/app.js""></script><script src=""/app.js""></script><script src=""/app.js""></script></body> </html> "; Regex regex = new Regex(pattern); string result = regex.Replace(input, substitution); } }

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