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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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"
"

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 = "(\\v)"; final String string = "line one&vellip;\n" + "line twoimport { CustomCacheKey } from '@layer0/core/router'\n\n" + "router.get('/some/path', ({ cache }) => {\n\n" + " cache({\n\n" + " key: new CustomCacheKey().addCookie('language').addCookie('currency'),\n\n" + " // Other options...\n\n" + " })\n\n" + "})import { CustomCacheKey } from '@layer0/core/router'\n\n" + "router.get('/some/path', ({ cache }) => {\n\n" + " cache({\n\n" + " browser: {\n\n" + " // Sets the cache-control: maxage=n header sent to the browser. To prevent the browser from caching this route\n\n" + " // set maxAgeSeconds: 0\n\n" + " maxAgeSeconds: 0,\n\n" + " // Sends a non-standard header `x-sw-cache-control: n` that you can use to control caching your service worker.\n\n" + " // Note that service workers do not understand this header by default, so you would need to add code to your service\n\n" + " // worker to support it\n\n" + " serviceWorkerSeconds: 60 * 60,\n\n" + " },\n\n" + " edge: {\n\n" + " // Sets the TTL for a response in Layer0's edge cache\n\n" + " maxAgeSeconds: 60 * 60 * 24,\n\n" + " // Sets the amount of time a stale response will be served from the cache. When a stale response is sent, Layer0\n\n" + " // will simultaneously fetch a new response to serve subsequent requests.\n\n" + " // Using stale-while-revalidate helps raise your effective cache hit rate to near 100%.\n\n" + " staleWhileRevalidateSeconds: 60 * 60, // serve stale responses for up to 1 hour while fetching a new response\n\n" + " // And many other options\n\n" + " },\n\n" + " // Optionally customizes the cache key for both edge and browser\n\n" + " key: new CustomCacheKey()\n\n" + " .addBrowser() // Split cache by browser type\n\n" + " .addCookie('some-cookie'), // Split cache by some-cookie cookie\n\n" + " })\n\n" + "})router.get('/scripts/:file', ({ serveStatic }) => {\n\n" + " serveStatic('path/to/scripts', {\n\n" + " permanent: true, // ensure that files are permanently accessible, even after a new version of the site has been deployed.\n\n" + " exclude: ['some-non-versioned-file.js'], // you can exclude specific files from being served permanently. You should do this for any files that do not have a hash of the content in the name.\n\n" + " })\n\n" + "})"; 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