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
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r"^(?!##?\s)([^\/\|\@\"!]*?)(##|#[@?$%]{1,3}#|\$@?\$)", flags=re.MULTILINE) test_str = ("## comment\n" "# #comment\n\n" "! Basic rules\n" "##div\n" "#@#div\n" "##.ads\n" "#@#.ads\n" "###ads\n" "#@##ads\n" "example.com,~example.org##div\n" "example.com,~example.org#@#div\n" "example.com,~example.org##.ads\n" "example.com,~example.org#@#.ads\n" "example.com,~example.org###ads\n" "example.com,~example.org#@##ads\n\n" "! HTML filtering rules\n" "! https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#html-filters\n" "example.com##^.badstuff\n" "example.com##^script:has-text(7c9e3a5d51cdacfc)\n" "! https://adguard.com/kb/general/ad-filtering/create-own-filters/#html-filtering-rules\n" "example.org$$script[data-src=\"banner\"]\n" "example.org$@$script[data-src=\"banner\"]\n\n" "! CSS rules\n" "! https://adguard.com/kb/general/ad-filtering/create-own-filters/#cosmetic-css-rules\n" "example.com#$#div { visibility: hidden; }\n" "example.com#@$#div { visibility: hidden; }\n" "example.com#$#.textad { visibility: hidden; }\n" "example.com#@$#.textad { visibility: hidden; }\n" "example.com#$##textad { visibility: hidden; }\n" "example.com#@$##textad { visibility: hidden; }\n\n" "! Extended CSS selectors\n" "! https://adguard.com/kb/general/ad-filtering/create-own-filters/#extended-css-selectors\n" "example.com#?#div:has(> a[target=\"_blank\"][rel=\"nofollow\"])\n" "example.com#@?#div:has(> a[target=\"_blank\"][rel=\"nofollow\"])\n" "example.com#?#.banner:matches-css(width: 360px)\n" "example.com#@?#.banner:matches-css(width: 360px)\n" "example.com#?##banner:matches-css(width: 360px)\n" "example.com#@?##banner:matches-css(width: 360px)\n\n" "example.com#$?#div:has(> span) { display: none !important; }\n" "example.com#@$?#div:has(> span) { display: none !important; }\n" "example.com#$?#.banner:has(> span) { display: none !important; }\n" "example.com#@$?#.banner:has(> span) { display: none !important; }\n" "example.com#$?##banner:has(> span) { display: none !important; }\n" "example.com#@$?##banner:has(> span) { display: none !important; }\n\n" "! JavaScript rules\n" "! https://adguard.com/kb/general/ad-filtering/create-own-filters/#javascript-rules\n" "! https://adguard.com/kb/general/ad-filtering/create-own-filters/#scriptlets\n" "example.com#%#window.__gaq = undefined;\n" "example.com#@%#window.__gaq = undefined;\n\n" "! Scriptlet rules\n" "example.com##+js(aopw, Fingerprint2)\n" "example.com#@#+js(aopw, Fingerprint2)\n" "example.org,example.com#%#//scriptlet(\"abort-on-property-read\", \"alert\")\n" "example.com#@%#//scriptlet(\"abort-on-property-read\")") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

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