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 = /^(?P<name>[\w\-\.]+)-(?P<version>v?\d+(\.\d+)?(\.\d+)?(-[\w\-]+(\.[\w\-]+)*)?(\+[\w\-]+(\.[\w\-]+)*)?)(?P<ext>\.[\w\-]+)$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?P<name>[\\w\\-\\.]+)-(?P<version>v?\\d+(\\.\\d+)?(\\.\\d+)?(-[\\w\\-]+(\\.[\\w\\-]+)*)?(\\+[\\w\\-]+(\\.[\\w\\-]+)*)?)(?P<ext>\\.[\\w\\-]+)$', 'gm') const str = `ansi-escapes-4.3.1.tgz babel-eslint-10.1.0.tgz chance-1.1.7.tgz cli-cursor-3.1.0.tgz eslint-7.13.0.tgz faker-5.1.0.tgz forever-monitor-3.0.1.tgz fs-extra-9.0.1.tgz lorem-ipsum-2.0.3.tgz micromatch-4.0.2.tgz mongoose-5.10.13.tgz puppeteer-5.4.1.tgz puppeteer-extra-3.1.15.tgz puppeteer-extra-plugin-stealth-2.6.3.tgz random-email-1.0.3.tgz random-useragent-0.5.0.tgz random-words-1.1.1.tgz slice-ansi-4.0.0.tgz uuid-8.3.1.tgz validator-13.1.17.tgz wrap-ansi-7.0.0.tgz font-awesome-5.11.2.tgz react-dom-16.13.1.tgz bootstrap-4.5.2.tgz moment-duration-format-2.3.2.tgz imagesloaded-4.1.tgz flickity-2.0.tgz lomster-1.tgz unicorn-1.2.3-alpha.10.beta.0.tgz rainbow-v1.1.1.tgz object.assign-4.1.4.tgz hello_world-0.0.3.tgz typescript-package-1-1.0.2.tgz `; // 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