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

~
~
mgu

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('^/foo/bar/+(?:(?:find|count)/*$(*SKIP)(*FAIL)|([^/\\r\\n\\t]+))/*$', 'mgu') const str = `--------------------must NOT get as id (reseved key words) /foo/bar/count /foo/bar/find --------------------must NOT get as id (not present) /foo/bar/ --------------------must NOT get as id (not present tab test) /foo/bar/ --------------------must NOT get as id (not present line break test) /foo/bar/ --------------------must NOT get as id (not present tab, line break, multiple slashes test) /foo/bar// / / // --------------------must get as id /foo/bar/1 /foo/bar/1c /foo/bar/c1 /foo/bar/sku /foo/bar/countfind /foo/bar/findcount /foo/bar/skucount /foo/bar/skufind /foo/bar/countsku /foo/bar/findsku /foo/bar/coun /foo/bar/fin /foo/bar/ount /foo/bar/ind /foo/bar/skucoun /foo/bar/skufin /foo/bar/finsku /foo/bar/counsku --------------------must get as id (unnecessary slash test) /foo/bar/1/ /foo/bar/1c/ /foo/bar/c1/ /foo/bar/sku/ /foo/bar/countfind/ /foo/bar/findcount/ /foo/bar/skucount/ /foo/bar/skufind/ /foo/bar/countsku/ /foo/bar/findsku/ /foo/bar/coun/ /foo/bar/fin/ /foo/bar/ount/ /foo/bar/ind/ /foo/bar/skucoun/ /foo/bar/skufin/ /foo/bar/finsku/ /foo/bar/counsku/ --------------------must get as id (unnecessary|invalid slashed test) /foo/bar///1/// /foo/bar///1c/// /foo/bar///c1/// /foo/bar///sku/// /foo/bar///countfind/// /foo/bar///findcount/// /foo/bar///skucount/// /foo/bar///skufind/// /foo/bar///countsku/// /foo/bar///findsku/// /foo/bar///coun/// /foo/bar///fin/// /foo/bar///ount/// /foo/bar///ind/// /foo/bar///skucoun/// /foo/bar///skufin/// /foo/bar///finsku/// /foo/bar///counsku///`; // 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