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

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"(\v)" test_str = ("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" "})") matches = re.search(regex, test_str) if matches: print ("Match was found at {start}-{end}: {match}".format(start = matches.start(), end = matches.end(), match = matches.group())) for groupNum in range(0, len(matches.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = matches.start(groupNum), end = matches.end(groupNum), group = matches.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and 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 Python, please visit: https://docs.python.org/3/library/re.html