How do I use predefined character classes regex?

In regex, you also have a number of predefined character classes that provide you with a shorthand notation for commonly used sets of characters.

Here are the list:

Predefined Class Matches
. Any character
d Any digit, shorthand for [0-9]
D A non digit, [^0-9]
s A whitespace character [^s]
S Any non whitespace character
w Word character [a-zA-Z_0-9]
W A non word character
package org.kodejava.example.regex;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PredefinedCharacterClassDemo {
    public static void main(String[] args) {
        // Define regex that will search a whitespace followed by f
        // and two any characters.
        String regex = "\\sf..";

        // Compiles the pattern and obtains the matcher object.
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(
            "The quick brown fox jumps over the lazy dog");

        // find every match and print it
        while (matcher.find()) {
            System.out.format("Text \"%s\" found at %d to %d.%n",
                matcher.group(), matcher.start(), matcher.end());
        }
    }
}

This program output the following result:

Text " fox" found at 15 to 19.

Wayan Saryada

Founder at Kode Java Org
I am a programmer, a runner, a recreational diver, currently live in the island of Bali, Indonesia. Mostly programming in Java, Spring Framework, Hibernate / JPA. You can support my works by donating here. Thank you 🥳

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.