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

/
/

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\\s+Content-[Tt]ype:\\s*\\S+"; final String string = "Accept-Ranges: bytes\n" + "Cache-Control: max-age=604800\n" + "Content-Type: text/html\n" + "Date: Fri, 14 Aug 2015 17:45:05 GMT\n" + "Etag: \"359670651\"\n" + "Expires: Fri, 21 Aug 2015 17:45:05 GMT\n" + "Last-Modified: Fri, 09 Aug 2013 23:54:35 GMT\n" + "Server: ECS (fty/2FA4)\n" + "X-Cache: HIT\n" + "x-ec-custom-error: 1\n" + "Content-Length: 1270\n\n\n" + "- 0%[ ] 0 --.-KB/s <!doctype html>\n" + "<html>\n" + "<head>\n" + " <title>Example Domain</title>\n\n" + " <meta charset=\"utf-8\" />\n" + " <meta http-equiv=\"Content-type\" content=\"text/html; charset=utf-8\" />\n" + " <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\" />\n" + " <style type=\"text/css\">\n" + " body {\n" + " background-color: #f0f0f2;\n" + " margin: 0;\n" + " padding: 0;\n" + " font-family: \"Open Sans\", \"Helvetica Neue\", Helvetica, Arial, sans-serif;\n" + " \n" + " }\n" + " div {\n" + " width: 600px;\n" + " margin: 5em auto;\n" + " padding: 50px;\n" + " background-color: #fff;\n" + " border-radius: 1em;\n" + " }\n" + " a:link, a:visited {\n" + " color: #38488f;\n" + " text-decoration: none;\n" + " }\n" + " @media (max-width: 700px) {\n" + " body {\n" + " background-color: #fff;\n" + " }\n" + " div {\n" + " width: auto;\n" + " margin: 0 auto;\n" + " border-radius: 0;\n" + " padding: 1em;\n" + " }\n" + " }\n" + " </style> \n" + "</head>\n\n" + "<body>\n" + "<div>\n" + " <h1>Example Domain</h1>\n" + " <p>This domain is established to be used for illustrative examples in documents. You may use this\n" + " domain in examples without prior coordination or asking for permission.</p>\n" + " <p><a href=\"http://www.iana.org/domains/example\">More information...</a></p>\n" + "</div>\n" + "</body>\n" + "</html>"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); if (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html