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
No Match

/
/
gxi

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r""" [ptkmnlswj]? (?:(?<=w)[aei]| (?<=[jt])[aeou]| (?<=[pkmnls])[aeiou]| (?<=\b)[aeiou]) (?:n(?![nm]?[aeiou]))? """ test_str = ("#Sanity Checks:\n" "---\n" "toki pona\n" "nanpa wan\n" "toki li pona mama tuliwan sulisuli \n" "mi olin e sina\n" "---\n\n" "#These should not work:\n" "---\n" "titijiji\n" "tanna\n" "nanma\n" "---\n\n" "#Some sentences from Wikipesija page for Linguistics:\n" "---\n" "toki Inli (kepeken toki Inli: EngLish) li toki suli.\n" "toki Inli li kama tan ma Piten. taso tenpo ni la jan li kepeken kin e toki Inli lon ma Mewika lon ma Kanata lon ma Oselija lon ma Nusilan. jan li toki kin e toki Inli lon ma ante mute. toki Inli li toki pi ma sike. toki Inli li jo e kepeken mute.\n" "---\n" "a an e en i in o on u un\n" "pa pan pe pen pi pin po pon pu pun\n" "ta tan te ten ti tin to ton tu tun\n" "ka kan ke ken ki kin ko kon ku kun\n" "ma man me men mi min mo mon mu mun\n" "na nan ne nen ni nin no non nu nun\n" "sa san se sen si sin so son su sun\n" "ja jan je jen ji jin jo jon ju jun\n" "la lan le len li lin lo lon lu lun\n" "wa wan we wen wi win wo won wu wun\n\n") matches = re.finditer(regex, test_str, re.VERBOSE | re.IGNORECASE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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