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

const regex = /(\w+(?=\/NN.?|JJ))/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(\\w+(?=\\\/NN.?|JJ))', 'gm') const str = `(S (NP cured/VBN ham/NN)) (S (NP cured/VBN smoked/VBD beef/NN)) (S (NP curry/NN powder/NN)) (S (NP custard/NN)) (S (NP custard/NN) (NP puerto/JJ rican/JJ style/NN)) (S (NP custard-apple/NN)) (S (NP cytosport/NN muscle/NN milk/NN ready-to-drink/NN)) (S (NP daiquiri/NN)) (S (NP daiquiri/NN) (NP prepared/VBN) --/: (NP recipe/VB)) (S (NP dandelion/NN) greens/NNS) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD butter/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD margarine/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD oil/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD boiled/VBN drained/JJ salt/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD fat/NN) (NP added/VBD cooking/NN ns/NN type/NN fat/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD fat/NN) (NP added/VBD cooking/NN)) (S (NP dandelion/NN) greens/NNS (NP cooked/VBD ns/JJ fat/NN) (NP added/VBD cooking/NN)) (S (NP danish/JJ dessert/NN pudding/NN)) (S (NP danish/JJ pastry/NN cheese/NN)) (S (NP danish/JJ pastry/NN cinnamon/NN) (NP enriched/VBD)) (S (NP danish/JJ pastry/NN cinnamon/NN) (NP unenriched/VBD)) (S (NP danish/JJ pastry/NN fruit/NN) (NP enriched/VBD includes/VBZ apple/NN cinnamon/NN raisin/NN lemon/NN raspberry/NN strawberry/NN)) (S (NP danish/JJ pastry/NN fruit/NN) (NP unenriched/VBD includes/VBZ apple/NN cinnamon/NN raisin/NN strawberry/NN)) (S (NP danish/JJ pastry/NN lemon/NN) (NP unenriched/VBD)) (S (NP danish/JJ pastry/NN raspberry/NN) (NP unenriched/VBD)) (S (NP dark/JJ) (NP chocolate/VB 45-59/JJ %/NN cocoa/NN)) (S (NP dark/JJ) (NP chocolate/VB 60-69/JJ %/NN cocoa/NN)) (S (NP dark/JJ) (NP chocolate/VB 70-85/JJ %/NN cocoa/NN)) (S (NP dark/JJ chocolate/NN) (NP coated/VBD coffee/NN) beans/NNS) (S (NP dasheen/NN) (NP boiled/VBD)) (S (NP dasheen/NN) (NP fried/VBD)) (S (NP date/NN candy/NN)) (S dates/NNS (NP deglet/VBP noor/JJ)) (S (NP decaf/NN coffee/NN)) (S (NP deer/NN chop/NN) (NP cooked/VBD)) (S (NP dehydrated/VBN milk/NN)) (S (NP dessert/NN dip/NN)) (S (NP dessert/NN pizza/NN)) (S (NP dessert/NN sauce/NN)) (S (NP dessert/NN topping/NN) (NP powdered/VBD)) (S (NP dessert/NN topping/NN) (NP powdered/VBD 1.5/CD) (NP ounce/NN) (NP prepared/VBD 1/2/CD) cup/NNS (NP milk/NN))`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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