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

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /(?sx)([ァ-ヺ])(?=.*:\1=(.))/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?sx)([ァ-ヺ])(?=.*:\\1=(.))', 'gm') const str = `ァ ア ィ イ ゥ ウ ェ エ ォ オ カ ガ キ ギ ク グ ケ ゲ コ ゴ サ ザ シ ジ ス ズ セ ゼ ソ ゾ タ ダ チ ヂ ッ ツ ヅ テ デ ト ド ナ ニ ヌ ネ ノ ハ バ パ ヒ ビ ピ フ ブ プ ヘ ベ ペ ホ ボ ポ マ ミ ム メ モ ャ ヤ ュ ユ ョ ヨ ラ リ ル レ ロ ヮ ワ ヰ ヱ ヲ ン ヴ ヵ ヶ ヷ ヸ ヹ ヺ Dictionary:ァ=ぁ:ア=あ:ィ=ぃ:イ=い:ゥ=ぅ:ウ=う:ェ=ぇ:エ=え:ォ=ぉ:オ=お:カ=か:ガ=が:キ=き:ギ=ぎ:ク=く:グ=ぐ:ケ=け:ゲ=げ:コ=こ:ゴ=ご:サ=さ:ザ=ざ:シ=し:ジ=じ:ス=す:ズ=ず:セ=せ:ゼ=ぜ:ソ=そ:ゾ=ぞ:タ=た:ダ=だ:チ=ち:ヂ=ぢ:ッ=っ:ツ=つ:ヅ=づ:テ=て:デ=で:ト=と:ド=ど:ナ=な:ニ=に:ヌ=ぬ:ネ=ね:ノ=の:ハ=は:バ=ば:パ=ぱ:ヒ=ひ:ビ=び:ピ=ぴ:フ=ふ:ブ=ぶ:プ=ぷ:ヘ=へ:ベ=べ:ペ=ぺ:ホ=ほ:ボ=ぼ:ポ=ぽ:マ=ま:ミ=み:ム=む:メ=め:モ=も:ャ=ゃ:ヤ=や:ュ=ゅ:ユ=ゆ:ョ=ょ:ヨ=よ:ラ=ら:リ=り:ル=る:レ=れ:ロ=ろ:ヮ=ゎ:ワ=わ:ヰ=ゐ:ヱ=ゑ:ヲ=を:ン=ん:ヴ=ゔ:ヵ=ヵ:ヶ=ヶ:ヷ=わ゙:ヸ=ゐ゙:ヹ=ゑ゙:ヺ=ヺ`; const subst = `$2`; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions