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About Ilias Tsagklis

Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.

Matcher groupCount example

In this example we shall show you how to use Matcher.groupCount() API method to get the number of capturing groups in a Matcher‘s pattern. To get the number of capturing groups in a matcher’s pattern one should perform the following steps:

  • Compile a String regular expression to a Pattern, using compile(String regex) API method of Pattern.
  • Use matcher(CharSequence input) API method of Pattern to create a Matcher that will match the given String input against this pattern.
  • Use groupCount() API method of Matcher to get the number of capturing groups in this matcher’s pattern,

as described in the code snippet below.

package com.javacodegeeks.snippets.core;

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

public class MatcherGroupCount {
  public static void main(String args[]) {


    Pattern pattern = Pattern.compile("B(ond)");

    String str = "My name is Bond. James Bond.";
    
    Matcher m = pattern.matcher(str);

    int numOfGroups = m.groupCount();
    
    System.out.println("number Of Groups =" + numOfGroups);

  }
}

Output:

number Of Groups : 1

 
This was an example of Matcher.groupCount() API method in Java.

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