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

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\\bStandard Deviation:\\h+\\K\\d[\\d.]*"; final String string = " Format: JPEG (Joint Photographic Experts Group JFIF format)\n" + " Geometry: 934x1189\n" + " Class: DirectClass\n" + " Type: true color\n" + " Depth: 8 bits-per-pixel component\n" + " Channel Depths:\n" + " Red: 8 bits\n" + " Green: 8 bits\n" + " Blue: 8 bits\n" + " Channel Statistics:\n" + " Red:\n" + " Minimum: 3855.00 (0.0588)\n" + " Maximum: 65535.00 (1.0000)\n" + " Mean: 44325.84 (0.6764)\n" + " Standard Deviation: 8571.68 (0.1308)\n" + " Green:\n" + " Minimum: 0.00 (0.0000)\n" + " Maximum: 65021.00 (0.9922)\n" + " Mean: 38079.03 (0.5810)\n" + " Standard Deviation: 8109.29 (0.1237)\n" + " Blue:\n" + " Minimum: 0.00 (0.0000)\n" + " Maximum: 61423.00 (0.9373)\n" + " Mean: 31937.17 (0.4873)\n" + " Standard Deviation: 8422.80 (0.1285)\n" + " Resolution: 72x72 pixels/inch\n" + " Filesize: 101.3Ki\n" + " Interlace: No\n" + " Orientation: Unknown\n" + " Background Color: white\n" + " Border Color: #DFDFDF\n" + " Matte Color: #BDBDBD\n" + " Page geometry: 934x1189+0+0\n" + " Compose: Over\n" + " Dispose: Undefined\n" + " Iterations: 0\n" + " Compression: JPEG\n" + " JPEG-Quality: 70\n" + " JPEG-Colorspace: 2\n" + " JPEG-Colorspace-Name: RGB\n" + " JPEG-Sampling-factors: 2x2,1x1,1x1\n" + " Signature: 68c70dc2aacc49610538d037e7913f66945d7655bb4acc83fa5e13c3581016a9\n" + " Profile-color: 456 bytes\n" + " Tainted: False\n" + " Elapsed Time: 0m:0.006050s\n" + " Pixels Per Second: 175.0Mi"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html