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 = "(?sm)(^[^\\r\\n]*)[\\r\\n](?=.*^\\1)"; final String string = "In 1881, Paul Gauguin joked about how to extract Cézanne's mysterious methods, instructing Camille Pissarro to \"ply him with one of those mysterious homeopathic drugs and come straight to Paris\n\n" + "In 1881, Paul Gauguin joked about how to extract Cézanne's mysterious methods, instructing Camille Pissarro to \"ply him with one of those mysterious homeopathic drugs and come straight to Paris to share the information\". The painter and critic Maurice Denis shared a sense of bewilderment about Cézanne's revoluti\n\n" + "Cézanne's mysterious methods, instructing Camille Pissarro to \"ply him with one of those mysterious homeopathic drugs and come straight to Paris to share the information\".\n\n" + "In 1881, Paul Gauguin joked about how to extract Cézanne's mysterious methods, instructing Camille Pissarro to \"ply him with one of those mysterious homeopathic drugs and come straight to Paris to share the information\".\n\n" + "He overturned centuries of theories about how the eye works by depicting a world constantly in motion, affected by the passing of time and infused with the artist's own memories and emotions.\n\n" + "In 1881, Paul Gauguin joked about how to extract Cézanne's mysterious methods, instructing Camille Pissarro to \"ply him with one of those mysterious homeopathic drugs and come straight to Paris to share the information\".\n"; 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