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 = /\bStandard Deviation:\h+\K\d[\d.]*/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\bStandard Deviation:\\h+\\K\\d[\\d.]*', 'gm') const str = ` Format: JPEG (Joint Photographic Experts Group JFIF format) Geometry: 934x1189 Class: DirectClass Type: true color Depth: 8 bits-per-pixel component Channel Depths: Red: 8 bits Green: 8 bits Blue: 8 bits Channel Statistics: Red: Minimum: 3855.00 (0.0588) Maximum: 65535.00 (1.0000) Mean: 44325.84 (0.6764) Standard Deviation: 8571.68 (0.1308) Green: Minimum: 0.00 (0.0000) Maximum: 65021.00 (0.9922) Mean: 38079.03 (0.5810) Standard Deviation: 8109.29 (0.1237) Blue: Minimum: 0.00 (0.0000) Maximum: 61423.00 (0.9373) Mean: 31937.17 (0.4873) Standard Deviation: 8422.80 (0.1285) Resolution: 72x72 pixels/inch Filesize: 101.3Ki Interlace: No Orientation: Unknown Background Color: white Border Color: #DFDFDF Matte Color: #BDBDBD Page geometry: 934x1189+0+0 Compose: Over Dispose: Undefined Iterations: 0 Compression: JPEG JPEG-Quality: 70 JPEG-Colorspace: 2 JPEG-Colorspace-Name: RGB JPEG-Sampling-factors: 2x2,1x1,1x1 Signature: 68c70dc2aacc49610538d037e7913f66945d7655bb4acc83fa5e13c3581016a9 Profile-color: 456 bytes Tainted: False Elapsed Time: 0m:0.006050s Pixels Per Second: 175.0Mi`; // 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