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*((((([0-9A-Fa-f]{1,4})|\*):){7}((([0-9A-Fa-f]{1,4})|\*)|:))|(((([0-9A-Fa-f]{1,4})|\*):){6}(:(([0-9A-Fa-f]{1,4})|\*)|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(((([0-9A-Fa-f]{1,4})|\*):){5}(((:(([0-9A-Fa-f]{1,4})|\*)){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(((([0-9A-Fa-f]{1,4})|\*):){4}(((:(([0-9A-Fa-f]{1,4})|\*)){1,3})|((:(([0-9A-Fa-f]{1,4})|\*))?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(((([0-9A-Fa-f]{1,4})|\*):){3}(((:(([0-9A-Fa-f]{1,4})|\*)){1,4})|((:(([0-9A-Fa-f]{1,4})|\*)){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(((([0-9A-Fa-f]{1,4})|\*):){2}(((:(([0-9A-Fa-f]{1,4})|\*)){1,5})|((:(([0-9A-Fa-f]{1,4})|\*)){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(((([0-9A-Fa-f]{1,4})|\*):){1}(((:(([0-9A-Fa-f]{1,4})|\*)){1,6})|((:(([0-9A-Fa-f]{1,4})|\*)){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:(([0-9A-Fa-f]{1,4})|\*)){1,7})|((:(([0-9A-Fa-f]{1,4})|\*)){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))\s*$", flags=re.MULTILINE) test_str = ("2404:6800:4003:c02::8a\n" "2404:6800:4003:804::200e\n" "2001:4998:c:a06::2:4008\n" "fe80::21d8:f50:c295:c4be\n" "2001:cdba::e:9652\n" "2001:cdba:0:0:0:0:3257:9652\n" "2001:cdba::3257:9652\n" "2001:cdba::1222\n" "21DA:D3:0:2F3B:2AA:FF:FE28:9C5A\n" "2001:cdba::1:2:3:3257:9652\n" "2404::4003:804::200e\n" "1234:Fd2:2:1:89::4500\n" "1234:Fd2:12:1:89::4500\n" "2001:DB8:0:0:0:0:0:*\n" "2001:DB8:0:0:0:*:*:*\n" "2001:DB8::0:*\n" "2001:DB8:0:0:0:*:0:1\n" "::\n" "2001:DB8:0:0:0:*\n" "2001:*:1\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