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

/
/
gmi

Test String

Code Generator

Language

Generated Code

const regex = /^#(?:[\da-f]{3}){1,2}$|^#(?:[\da-f]{4}){1,2}$|(rgb|hsl)a?\((\s*-?\d+%?\s*,){2}(\s*-?\d+%?\s*)\)|(rgb|hsl)a?\((\s*-?\d+%?\s*,){3}\s*(0|(0?\.\d+)|1)\)/gmi; // Alternative syntax using RegExp constructor // const regex = new RegExp('^#(?:[\\da-f]{3}){1,2}$|^#(?:[\\da-f]{4}){1,2}$|(rgb|hsl)a?\\((\\s*-?\\d+%?\\s*,){2}(\\s*-?\\d+%?\\s*)\\)|(rgb|hsl)a?\\((\\s*-?\\d+%?\\s*,){3}\\s*(0|(0?\\.\\d+)|1)\\)', 'gmi') const str = `#ff0 #ff00 #ff00f #ff00ff #ff00ff0 #ff00ff00 rgb(0, 0, 0) rgb(0,) rgb(0 0) rgb( 0, 0, 0 ) rgb(-100, -10, 0 ) rgb(0, 0, 0,) rgb(-100, -10 0 ) rgb(-100 -10 0 , , ,) rgb(100%, 100%, 100%) hsl(100%, 100%, 100%, 1009) rgb(0,0,0,1.2) rgb(0, 0 , 0 , 1.2) rgb(0,0,0, 0.4) rgb(0,0,0, 0.499) rgb(0, 0 , 0 ) rgba(0, 0, 0, 1) rgba(0, 0, 0, 0) rgba( 0, 0, 0, 1) rgba(0, 0, 0, .45) rgba(0, 0, 0, .4) rgba(0,0,0, 1.2) rgba(100%, 100%, 100%, 1) hsl(0, 0, 0) hsl(0,) hsl(0 0) hsl( 0, 0, 0 ) hsl(-100, -10, 0 ) hsl(-100 , -10, 0 ) hsl(0, 0, 0,) hsl(-100, -10 0 ) hsl(-100 -10 0 , , ,) hsl(100%, 100%, 100%) hsl(100%, 100%, 100%, 1009) hsl(0,0,0,1.2) hsl(0, 0 , 0 , 1.2) hsl(0,0,0, 0.4) hsl(0,0,0, 0.499) hsl(0, 0 , 0 ) hsla(0, 0, 0, 1) hsla(0, 0, 0, .45) hsla(0, 0, 0, .4) hsla(0,0,0, 1.2) hsla(100%, 100%, 100%, 1)`; // 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