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

/
/
gm

Test String

Code Generator

Generated Code

const regex = /\b(ATU\d{8}|BE[01]\d{9}|BG\d{9,10}|CY\d{8}[LX]|CZ\d{8,10}|DE\d{9}|DK\d{8}|EE\d{9}|EL\d{9}|ES[\dA-Z]\d{7}[\dA-Z]|FI\d{8}|FR[\dA-Z]{2}\d{9}|HR\d{11}|HU\d{8}|IE\d{7}[A-Z]{2}|IT\d{11}|LT(\d{9}|\d{12})|LU\d{8}|LV\d{11}|MT\d{8}|NL\d{9}B\d{2}|PL\d{10}|PT\d{9}|RO\d{2,10}|SE\d{12}|SI\d{8}|SK\d{10})\b/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\b(ATU\\d{8}|BE[01]\\d{9}|BG\\d{9,10}|CY\\d{8}[LX]|CZ\\d{8,10}|DE\\d{9}|DK\\d{8}|EE\\d{9}|EL\\d{9}|ES[\\dA-Z]\\d{7}[\\dA-Z]|FI\\d{8}|FR[\\dA-Z]{2}\\d{9}|HR\\d{11}|HU\\d{8}|IE\\d{7}[A-Z]{2}|IT\\d{11}|LT(\\d{9}|\\d{12})|LU\\d{8}|LV\\d{11}|MT\\d{8}|NL\\d{9}B\\d{2}|PL\\d{10}|PT\\d{9}|RO\\d{2,10}|SE\\d{12}|SI\\d{8}|SK\\d{10})\\b', 'gm') const str = `ATU12345678 BE1234567890 BG123456789 HR12345678901 CY12345678X CZ12345678 DK12345678 EE123456789 FI12345678 FR12345678901 DE123456789 EL123456789 HU12345678 IE1234567WA IT12345678901 LV12345678901 LT123456789 LU12345678 MT12345678 NL123456789B01 PL1234567890 PT123456789 RO1234567890 SK1234567890 SI12345678 ESX12345678 SE123456789012`; // 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