Posix Character Class \p{Alnum} Match



The character class \p{Alnum} matches any alphanumeric character.


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

package com.tutorialspoint;

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

public class PosixCharacterClassDemo {
   private static final String REGEX = "\\p{Alnum}";
   private static final String INPUT = "Bb12\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(): 0
Match String start(): 1
Match String start(): 2
Match String start(): 3
Match String start(): 5