MatchResult groupCount() method in Java with examples.

The java.util.regex.MatcheResult interface provides methods to retrieve the results of a match.

You can get an object of this interface using the toMatchResult() method of the Matcher class. This method returns a MatchResult object which represents the match state of the current matcher.

The groupCount() method of this interface counts and returns the number of groups in the regular expression of the current object.

Example

import java.util.Scanner;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GroupCount {
   public static void main( String args[] ) {
      String regex = "(.*)(\\d+)(.*)";
      //Reading input from user
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter input text: ");
      String input = sc.nextLine();
      //Instantiating the Pattern class
      Pattern pattern = Pattern.compile(regex);
      //Instantiating the Matcher class
      Matcher matcher = pattern.matcher(input);
      //verifying whether a match occurred
      if(matcher.find()) {
         System.out.println("Match found");
      }
      MatchResult res = matcher.toMatchResult();
      int count = res.groupCount();
      System.out.println("No.of groups: "+count);
   }
}

Output

Enter input text:
This is a sample Text, 123
Match found
No.of groups: 3