Predefined Character Class \d Match

Description

The character class \d matches any digit from 0 to 9.

Example

The following example shows the usage of Predefined character class matching.

package com.tutorialspoint;

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

public class PredefinedCharacterClassDemo {
   private static final String REGEX = "\\d";
   private static final String INPUT = "dbcabcab12\tc";

   public static void main(String[] args) {
      // create a pattern
      Pattern  pattern = Pattern.compile(REGEX);
      
      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 

      while(matcher.find()) {
         //Prints the start index of the match.
         System.out.println("Match String start(): "+matcher.start());
      }
   }
}

Let us compile and run the above program, this will produce the following result −

Match String start(): 8
Match String start(): 9