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"<a.*href.?=.?[\"'](?:\b\w+://)?([\w-]+(?:\.[\w-]+)+)[/:?]?.*?[\"'].*?>?(?:</)?.?>") test_str = ("<a href=\"http://stepic.org/courses\">\n" "<a href='https://stepic.org'>\n" "<a href='http://neerc.ifmo.ru:1345'>\n" "<a href=\"ftp://mail.ru/distib\" >\n" "<a href=\"ya.ru\">\n" "<a href=\"www.ya.ru\">\n" "<a href=\"../skip_relative_links\">\n" "<a target=\"blank\" href='http://sas-_0123d.ifmo.ru:1345'>\n" "<a href='http://neerc.ifmo.ru:1345'>\n" "<a href=\"../some_path/index.html\">\n" "<a href=\"https://www.ya.ru\">\n" "<a href=\"ftp://mail.ru/distib\" >\n" "<a href=\"bya.ru\">\n" "<a href=\"http://www.ya.ru\">\n" "<a href=\"www.kya.ru\">\n" "<a href=\"../skip_relative_links\">\n" "<a href=\"http://stepic.org/courses\">\n" "<a class = \"hello\" href= \"http://ftepic.org/courses\" id=\"dfdf\">\n" "<p class = \"hello\" href= \"http://dtepic.org/courses\">\n" "<a class = \"hello\" href = \"http://a.b.vc.ttepic.org/courses\">\n" "<a href='https://stepic.org'>\n" "<a href='http://neerc.ifmo.ru:1345' >\n" "<a href = \"ftp://mail.ru/distib\" >\n" "<a href= \"ya.ru\">\n" "<a href =\"www.ya.ru\">\n" "<a href=\"../skip_relative_links\">\n" "<link rel=\"image_src\" href=\"https://examaple.org/files/6a2/72d/e09/6a272de0944f447fb5972c44cc02f795.png\" />\n" "<a href=\"http://www.gtu.edu.ge/index_e.htm\" target=\"_top\">Georgian Technical University</a>\n" "<a href=\"http://stepic-2.org/courses\">\n" "<a href=\"ftp://www.mya-2.ru\">\n" "<a href='https://stepic-2.org'>\n" "<a link href='http://neerc.ifmo-2.ru:1345'>\n" "<a title=test download=\"http://test.com\"; href=\"test.com\" class=\"my test\" style=>\n" "<a title=test class=\"my test\" href= \"test1.com:8080/test/path?get=http://test2.ru/?true\"; rel=\"nofollow\" style=>\n" "<a title=test meta=\"whatever http://test1.com\"; href = \"test.com?get=http://test2.ru/?true\"; class=\"my test\" style= >\n" "<a target=\"blank\" href='http://sasd.ifmo-2.ru:1345'>\n" "<a href='http://neerc.ifmo-2.ru:1345'>\n" "<a href=\"../some_path/index-2.html\">\n" "<a href=\"https://www.ya-2.ru\">\n" "<a href=\"ftp://mail-2.ru/distib\" >\n" "<a href=\"bya-2.ru\">\n" "<a href=\"http://www.ya-2.ru\">\n" "<a href=\"www.kya-2.ru\" >\n" "<a href=\"../skip_relative_links-2\">\n" "<a href=\"http://stepic-2.org/courses\">\n" "<a class = \"hello-2\" href= \"http://ftepic-2.org/courses\" id=\"dfdf\">\n" "<p class = \"hello-2\" href= \"http://dtepic-2.org/courses\">\n" "<a class = \"hello-2\" href = \"http://a.b.vc.ttepic-2.org/courses\">\n" "<a href='https://stepic-2.org'>\n" "<a href='http://neerc.ifmo-2.ru:1345' >\n" "<a href = \"ftp://mail-2.ru/distib\" >\n" "<a href= \"ya-2.ru\">\n" "<a href =\"www.ya-2.ru\">\n" "<a href=\"../skip_relative_links\">\n" "<link rel=\"image_src\" href=\"https://examaple.org/files/6a2/72d/e09/6a272de0944f447fb5972c44cc02f795.png\" />\n" "<a href=\"http://www.gtu.edu-2.ge/index_e.htm\" target=\"_top\">Georgian Technical University</a>\n" "<a class-8 = \"hello-2\" href= \"http://zzz.last.test-1.stepic.org/courses\" id=\"dfdf\">\n" "<a class-4-4 = \"hello-2-raz\" href = \"http://zzz.last.test-2.stepic.org/courses\" >\n" "<a href =\"https://stepic.org/media/attachments/lesson/24471/02\">") 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