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

/
/
gm

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"^(?(DEFINE)(?'word'(?:[a-zA-Z0-9!?'\"&\.,+@%~$]|(?<! )-(?! ))+)(?'words'(?&word)(?: (?&word))*?)(?'nothe'(?<!, (?i:a))(?<!, (?i:the|les)))(?'ver_prefix'Rev|Proto|Alpha|Beta))(?'title'(?&words)(?&nothe))(?'subtitle' - (?&words))*?(?'upd' (?:Update|DLC - (?&words)))?(?'region' \((?:(?:A|As|B|C|Ch|Nl|E|F|G|Gr|Hk|I|J|K|No|R|S|Sw|U|Uk|Tw|W))+\))?(?'version' \[(?:(?:(?&ver_prefix) )?(?:(?'_ver'[\da-zA-Z]+)(?:\.(?&_ver))+|\d\d\d\d-\d\d-\d\d(?:T\d+)?)|(?&ver_prefix)( (?:[A-Z]|\d+|early))?)\])?(?'part' \(Dis(?:c|k) \d+\))?(?'language' \((?'_lang'(?:F-)?(?:Ja|En|Fr|De|Es|It|Nl|Ca|Fi|No|Sv|Da|Zh(?:-Hant|-Hans)?|Pt|Ru|Ko|Pl))(?:,?(?&_lang))*\))?(?'randomshit'(?: \[DEMO\])?(?'lossy' \[LOSSY\])?(?: \[Sample\])?(?: \(Promo\))?(?: \(Unl\))?)(?'features' \[(?'_feat'[a-zA-Z]+)(?:, ?(?&_feat))*\])?(?'ext'\.(?:gbc|gb|nsp|xci|(nkit\.)?rvz|gcz|wbfs|wad|gba|type|cia|3ds|nds|nes|sfc|smc|n64|z64|wux|gg|md|sms|iso|pce|chd))$" test_str = ("Amazing Spider Man (UE).gb\n" "Otto's Ottifanten - Baby Bruno's Nightmare (E) (En,Fr,De,Es).gb\n" "Pokemon Kristall (G).gbc\n" "A Hat in Time DLC - Nyakuza Metro [1.1.0].nsp\n" "Pokemon Card GB2 - GR Dan Sanjou! (J).gbc\n" "Asphalt 9 Legends [1.3.1].nsp\n" "Animal Crossing New Horizons DLC - Special Order Ticket Pocket Camp tie-in campaign.nsp\n" "Pokemon Pinball (E) (En,Fr,De,Es,It) [S,DMG].gbc\n" "Arcade Hits - Moon Patrol & Spy Hunter (UE) [DMG].gbc\n" "Daikatana (U) [Proto 2000-04-19] [DMG].gbc\n" "Hang Time Basketball (E) (Unl).gbc\n" "Pokemon Green (J) [1.0] (F-En).gb\n" "LSDJ [9.2.L].gb\n" "Keep Talking and Nobody Explodes Update [1.2.0].nsp\n" "Sonic Mania Plus [1.0.4] (En,Ja,Fr,De,Es,It,Zh).xci\n" "Spelunky [1.22.2a].nsp\n" "Chrono Cross (U) (Disc 1).chd\n" "Chrono Cross (U) (Disc 2).chd\n" "Fear Effect 2 - Retro Helix (E) (Disc 1) (En,Fr,De).chd\n" "Ren & Stimpy Show - Buckeroo$! (U).sfc\n" "PGA European Tour Golf (E) [Beta B.29] (En,De).z64\n" "007 - The World Is Not Enough (U) [Beta 21].z64\n" "007 - The World Is Not Enough (U) [Beta 2.00].z64\n" "Pokemon Yellow (UE) [C].gb\n" "Shadowgate 64 - Trials of the Four Towers (U) [Beta] (En,Es).z64\n" "Mario Kart Wii (U) (En,Fr,Es) [LOSSY].wbfs") matches = re.finditer(regex, test_str, re.MULTILINE) 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