Regular Expression Metacharacter in Java

The subexpression/metacharacter “\t” matches the tab spaces.

Example 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
   public static void main( String args[] ) {
      String regex = "\t";
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a string: ");
      String input = sc.nextLine();
      Pattern p = Pattern.compile(regex);
      Matcher m = p.matcher(input);
      int count = 0;
      while(m.find()) {
         count ++;
      }
      System.out.println("Number of tab spaces: "+count);
   }
}

Output

Enter a string:
This    is    a    sentence    with    tab    spaces
Number of tab spaces: 6

Example 2

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
   public static void main( String args[] ) {
      String regex = "\t";
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a string: ");
      String input = sc.nextLine();
      Pattern p = Pattern.compile(regex);
      Matcher m = p.matcher(input);
      int count = 0;
      String result = "";
      while(m.find()) {
         result = m.replaceAll(" ");
      }
      System.out.println("Result: "+result);
   }
}

Output

Enter a string:
This is a sentence with tab spaces
Result: This is a sentence with tab spaces