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"(?#URI)^(?#\n" r" Scheme )(?<Scheme>[a-z][a-z0-9\+\-\.]*):(?#\n" r" HeirPart)(?<HierPart>\/\/(?#\n" r" Authority)(?<Authority>(?#\n" r" UserInfo)((?<UserInfo>(\%[0-9a-f][0-9a-f]|[a-z0-9\-\.\_\~]|[\!\$\&\'\(\)\*\+\,\;\=]|\:)*)\@)?(?#\n" r" Host )(?<Host>(?#\n" r" IP Literal)\[((?#\n" r" IPv6 Address )(?<IPv6>((?<IPv6_1_R_H16>[0-9a-f]{1,4})\:){6,6}(?<IPV6_1_R_LS32>((?<IPV6_1_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_1_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_1_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_1_R_LS32_H16_2>[0-9a-f]{1,4}))|\:\:((?<IPV6_2_R_H16>[0-9a-f]{1,4})\:){5,5}(?<IPV6_2_R_LS32>((?<IPV6_2_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_2_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_2_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_2_R_LS32_H16_2>[0-9a-f]{1,4}))|(?<IPV6_3_L_H16>[0-9a-f]{1,4})?\:\:((?<IPV6_3_R_H16>[0-9a-f]{1,4})\:){4,4}(?<IPV6_3_R_LS32>((?<IPV6_3_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_3_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_3_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_3_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_4_L_H16_REPEAT>[0-9a-f]{1,4})\:)?(?<IPV6_4_L_H16>[0-9a-f]{1,4}))?\:\:((?<IPV6_4_R_H16>[0-9a-f]{1,4})\:){3,3}(?<IPV6_4_R_LS32>((?<IPV6_4_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_4_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_4_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_4_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_5_L_H16_REPEAT>[0-9a-f]{1,4})\:){0,2}(?<IPV6_5_L_H16>[0-9a-f]{1,4}))?\:\:((?<IPV6_5_R_H16>[0-9a-f]{1,4})\:){2,2}(?<IPV6_5_R_LS32>((?<IPV6_5_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_5_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_5_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_5_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_6_L_H16_REPEAT>[0-9a-f]{1,4})\:){0,3}(?<IPV6_6_L_H16>[0-9a-f]{1,4}))?\:\:(?<IPV6_6_R_H16>[0-9a-f]{1,4})\:(?<IPV6_6_R_LS32>((?<IPV6_6_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_6_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_6_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_6_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_7_L_H16_REPEAT>[0-9a-f]{1,4})\:){0,4}(?<IPV6_7_L_H16>[0-9a-f]{1,4}))?\:\:(?<IPV6_7_R_LS32>((?<IPV6_7_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}(?<IPV6_7_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_7_R_LS32_H16_1>[0-9a-f]{1,4})\:(?<IPV6_7_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_8_L_H16_REPEAT>[0-9a-f]{1,4})\:){0,5}(?<IPV6_8_L_H16>[0-9a-f]{1,4}))?\:\:(?<IPV6_8_R_H16>[0-9a-f]{1,4})|(((?<IPV6_9_L_H16_REPEAT>[0-9a-f]{1,4})\:){0,6}(?<IPV6_9_L_H16>[0-9a-f]{1,4}))?\:\:)|(?#\n" r" IPvFuture Address)v[a-f0-9]+\.([a-z0-9\-\.\_\~]|[\!\$\&\'\(\)\*\+\,\;\=]|\:)+(?#\n" r" ))\]|(?#\n" r" IPv4 Address)(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3,3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?#\n" r" RegName)([a-z0-9\-\.\_\~]|\%[0-9a-f][0-9a-f]|[\!\$\&\'\(\)\*\+\,\;\=])*(?#\n" r" ))(?#\n" r" Port )(:(?<Port>[0-9]+))?(?#\n" r" ))(?#\n" r" Path )(?<Path>(\/([a-z0-9\-\.\_\~\!\$\&\'\(\)\*\+\,\;\=\:\@]|(%[a-f0-9]{2,2}))*)*)(?#\n" r" ))(?#\n" r" Query )(?<Query>\?([a-z0-9\-\.\_\~\!\$\&\'\(\)\*\+\,\;\=\:\@\/\?]|(%[a-f0-9]{2,2}))*)?(?#\n" r" Fragment)(?<Fragment>#([a-z0-9\-\.\_\~\!\$\&\'\(\)\*\+\,\;\=\:\@\/\?]|(%[a-f0-9]{2,2}))*)?(?#\n" r")$"), flags=re.IGNORECASE | re.MULTILINE) test_str = ("http://helloworld.com/\n" "foo+://example.com:8042/over/there?name=ferret#nose\n" "foo+://andrewj:myPassword:mySecondPassword@example.com:8042/over/there?name=ferret#nose\n\n" "urn:example:animal:ferret:nose\n\n" "http://10.15.20.73/\n" "http://user.@com/") 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