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]
  • Character class intersection
    [\w&&[^\d]]
  • 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
Processing...

Test String

Code Generator

Generated Code

const regex = /^(\+ *|- *)?((?!0+)\d*?|(?!0{2,})\d*?\.(?!0+)\d*?)('|")$|^(\+ *|- *)? *(?!0+)\d+?' *-? *(\d+?|\d*?\.\d*?)"$|^((\+ *|- *)?((?!0+)|0 )\d*? *(?!0+)\d+?\/(?!0+)\d+?('|"))$/mg; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(\\+ *|- *)?((?!0+)\\d*?|(?!0{2,})\\d*?\\.(?!0+)\\d*?)(\'|")$|^(\\+ *|- *)? *(?!0+)\\d+?\' *-? *(\\d+?|\\d*?\\.\\d*?)"$|^((\\+ *|- *)?((?!0+)|0 )\\d*? *(?!0+)\\d+?\\\/(?!0+)\\d+?(\'|"))$', 'mg') const str = ` - + - x 20'-4" + 20' - 20' 20'3" 20'-3" 20' - 40" -20'-20" 20'00" 20.45" 20.45' 00.45' 00.45" 00" 00' +20' - 0.45" 20' - .45" .20'-4" 0.30'-4" 20' 20'P 20" 20"P 0.20' .20' a' b" - 20 1/2' + 20 22/128" 20 0/2" 20 00/12' -1/2" + 1/2' 0/2" 00/22" + 01/2" 23 00/30' 23 12/03' 23 02/20" 0 2/3' 00 2/3' - 11 2/3' 2 22' 2 22/03' 2 3/2 23 00/30 23 12/03 23 02/20 23/34" 23/23.4" asf sf" `; // 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