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

/
/
img

Test String

Code Generator

Language

Generated Code

const regex = /^(?:((?:IT|SM)\d{2}[A-Z]{1}\d{22})|(NL\d{2}[A-Z]{4}\d{10})|(LV\d{2}[A-Z]{4}\d{13})|((?:BG|GB|IE)\d{2}[A-Z]{4}\d{14})|(GI\d{2}[A-Z]{4}\d{15})|(RO\d{2}[A-Z]{4}\d{16})|(MT\d{2}[A-Z]{4}\d{23})|(NO\d{13})|((?:DK|FI|FO)\d{16})|((?:SI)\d{17})|((?:AT|EE|LU|LT)\d{18})|((?:HR|LI|CH)\d{19})|((?:DE)\d{20})|((?:CZ|ES|SK|SE)\d{22})|(PT\d{23})|((?:IS)\d{24})|((?:BE)\d{14})|((?:FR|MC|GR)\d{25})|((?:PL|HU|CY)\d{26}))$/img; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?:((?:IT|SM)\\d{2}[A-Z]{1}\\d{22})|(NL\\d{2}[A-Z]{4}\\d{10})|(LV\\d{2}[A-Z]{4}\\d{13})|((?:BG|GB|IE)\\d{2}[A-Z]{4}\\d{14})|(GI\\d{2}[A-Z]{4}\\d{15})|(RO\\d{2}[A-Z]{4}\\d{16})|(MT\\d{2}[A-Z]{4}\\d{23})|(NO\\d{13})|((?:DK|FI|FO)\\d{16})|((?:SI)\\d{17})|((?:AT|EE|LU|LT)\\d{18})|((?:HR|LI|CH)\\d{19})|((?:DE)\\d{20})|((?:CZ|ES|SK|SE)\\d{22})|(PT\\d{23})|((?:IS)\\d{24})|((?:BE)\\d{14})|((?:FR|MC|GR)\\d{25})|((?:PL|HU|CY)\\d{26}))$', 'img') const str = `SEPA SM07U0854009803000030174419 SI56011006000005649 ES1321000555370200853027 CY02002001950000357009822416 NOT SEPA SC74NOVH00000021002035257028SCR TN5901026067111999766058 UA123052990004149497803982794`; // 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