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

/
/

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^[\\s\\S]*?(?=\\n{2,})"; final String string = "The War of the Worlds\n" + "10-10-2020\n\n" + "I.\n" + "THE EVE OF THE WAR.\n\n" + "No one would have believed in the last years of the nineteenth century\n" + "that this world was being watched keenly and closely by intelligences\n" + "greater than man’s and yet as mortal as his own; that as men busied\n" + "themselves about their various concerns they were scrutinised and\n" + "studied, perhaps almost as narrowly as a man with a microscope might\n" + "scrutinise the transient creatures that swarm and multiply in a drop of\n" + "water. With infinite complacency men went to and fro over this globe\n" + "about their little affairs, serene in their assurance of their empire\n" + "over matter. It is possible that the infusoria under the microscope do\n" + "the same. No one gave a thought to the older worlds of space as sources\n" + "of human danger, or thought of them only to dismiss the idea of life\n" + "upon them as impossible or improbable. It is curious to recall some of\n" + "the mental habits of those departed days. At most terrestrial men\n" + "fancied there might be other men upon Mars, perhaps inferior to\n" + "themselves and ready to welcome a missionary enterprise. Yet across the\n" + "gulf of space, minds that are to our minds as ours are to those of the\n" + "beasts that perish, intellects vast and cool and unsympathetic,\n" + "regarded this earth with envious eyes, and slowly and surely drew their\n" + "plans against us. And early in the twentieth century came the great\n" + "disillusionment.\n"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); if (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