Regular Expressions 101

Save & Manage Regex

  • Current Version: 1
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
There are currently no sponsors. Become a sponsor today!
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=([\"\'])?((?:.(?!\1|>))*.?)\1?", flags=re.IGNORECASE) test_str = ("<li class=\"navItem \"><a href=\"/services/\" lang=\"de\" hreflang=\"de\">Services</a></li>\n" "<a class=\"iMacLink\" href=\"/portfolio/\" ><div class=\"iMacOverlay\"></div><div class=\"\">Super</div></a></div>\n" "<div class=\"addthis_toolbox addthis_default_style\">\n" "<a itemprop=\"url\" target=\"_blank\" href=\"https://www.facebook.com/any-profile\" title=\"facebook\" class=\"facebookSite\"><span class=\"icon-facebook\"></span></a>\n" "<a itemprop=\"url\" target=\"_blank\" href=\"https://twitter.com/any-profile\" title=\"twitter\" class=\"twitterSite\"><span class=\"icon-twitter\"></span></a>\n" "<a itemprop=\"url\" target=\"_blank\" href=\"https://pinterest.com/any-profile\" title=\"pinterest\" class=\"pinterestSite\"><span class=\"icon-pinterest\"></span></a>\n" "<a itemprop=\"url\" target=\"_blank\" href=\"//feeds.feedburner.comany-profile?format=xml\" title=\"rss\" class=\"rss\"><span class=\"icon-rss\"></span></a>\n" "</div>\n\n\n" "<a class=\"social facebookProfil\" href=\"http://www.facebook.com/any-profile\">Facebook</a>\n" "<a class=\"social facebookProfil\" href='https://www.facebook.com/single-quotes'>Facebook</a>\n" "<a class=\"social facebookProfil\" href=https://www.facebook.com/no-quotes>Facebook</a>\n" "<a class=\"social youtubeProfil\" href=\"http://www.youtube.com/user/any-profile\">Youtube</a>\n\n" "<a class=\"social vimeoProfil\" href=\"http://vimeo.com/any-profile\">Vimeo</a>\n" "<a class=\"social xingProfil\" href=\"https://www.xing.com/companies/any-profile\">XING</a>\n" "<a class=\"social twitterProfil\" href=\"https://twitter.com/any-profile\">Folge bei Twitter</a>\n\n" "<a href=\"https://www.instagram.com/p/CN-Kx40nOW0/\">Instagram Beitrag</a>\n" "<a href=\"http://instagram.com/quellenhofaachen\">Instagram Profil</a>\n" "<a href=\"https://www.instagram.com/explore/tags/url\">Instagram Tag-Url</a>\n" "<A href=\"https://www.Instagram.com/uppercase-link\">Upercase-link</A>\n\n" "<a href=\"http://instagram.com/unique\">Unique-test http</a>\n" "<a href=\"//instagram.com/unique\">Unique-test protocol relative</a>\n" "<a href=\"https://instagram.com/unique\">Unique-test https</a>\n" "<a href=\"http://www.instagram.com/unique\">Unique-test www</a>\n\n\n") 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