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"(?<scheme>[^!$&'()*,;=@//:\s]+):(?<authority>//(?<userinfo>(?<username>[\w\.\-!$&'()*,;=]+):?(?<password>[\w\.\-!$&'()*,;=]+)?@)?(?<host>[^\s\n\t\r/:\[\]]+|\[[^\s\n\t\r/:\[\]]+\]):?(?<port>\d{1,5})?)?[/]?(?<path>[^\s\?#]{1,}(?:\?(?<query>[^\s#]+))?(?:#(?<fragment>[^\s]+))?)?") test_str = ("example from wikipedia URI:\n" " userinfo host port\n" " ┌─┴─────┐\n" " user pass\n" " ┌──┴───────┴───┐┌──────┴──────┐ ┌┴─┐\n" " https://john.doe:example@www.example.com:1234/forum/questions/?tag=networking&order=newest#top\n" " └─┬─┘ └─────────────┬─────────────┘└───────┬───────┘ └────────────┬────────────┘ └┬┘\n" " scheme authority path query fragment\n" " userinfo host port\n" " ┌──┴───┐ ┌──────┴──────┐ ┌┴─┐\n" " https://john.doe@www.example.com:1234/forum/questions/?tag=networking&order=newest#:~:text=whatever\n" " └─┬─┘ └─────────────┬─────────────┘└───────┬───────┘ └────────────┬────────────┘ └───────┬───────┘\n" " scheme authority path query fragment\n\n" " ldap://[2001:db8::7]/c=GB?objectClass?one\n" " └┬─┘ └─────┬─────┘└─┬─┘ └──────┬──────┘\n" " scheme authority path query\n\n" " mailto:John.Doe@example.com\n" " └─┬──┘ └────┬─────────────┘\n" " scheme path\n\n" " news:comp.infosystems.www.servers.unix\n" " └┬─┘ └─────────────┬─────────────────┘\n" " scheme path\n\n" " tel:+1-816-555-1212\n" " └┬┘ └──────┬──────┘\n" " scheme path\n\n" " telnet://192.0.2.16:80/\n" " └─┬──┘ └─────┬─────┘│\n" " scheme authority path\n\n" " urn:oasis:names:specification:docbook:dtd:xml:4.1.2\n" " └┬┘ └──────────────────────┬──────────────────────┘\n" " scheme path") 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