Matcher group(String) method in Java with Examples

The group(String string) method of Matcher Class is used to get the group of the match result already done, from the specified string.

Syntax:

public String group(String string)

Parameters: This method takes a parameter string which is the String from which the group index of the matched pattern is required.

Return Value: This method returns the group of the matched group from the specified string.

Exception: This method throws:

• IllegalStateException if no match has yet been attempted, or if the previous match operation failed.
• IndexOutOfBoundsException if there is no capturing group in the pattern with the given name.

Below examples illustrate the Matcher.group() method:

Example 1:

// Java code to illustrate end() method

import java.util.regex.*;

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

        // Get the regex to be checked
        String regex = "\\b(?<Geeks>[A-Za-z\\s]+)";

        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);

        // Get the String to be matched
        String stringToBeMatched
            = "GeeksForGeeks";

        // Create a matcher for the input String
        Matcher matcher
            = pattern
                  .matcher(stringToBeMatched);

        // Get the current matcher state
        MatchResult result
            = matcher.toMatchResult();
        System.out.println("Current Matcher: "
                           + result);

        while (matcher.find()) {
            // Get the group matched using group() method
            System.out.println(matcher.group("Geeks"));
        }
    }
}

Output:

Current Matcher: java.util.regex.Matcher[pattern=\b(?[A-Za-z\s]+) region=0,13 lastmatch=]
GeeksForGeeks

Example 2:

// Java code to illustrate end() method

import java.util.regex.*;

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

       // Get the regex to be checked
        String regex = "\\b(?<GFG>[A-Za-z\\s]+)";

        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);

        // Get the String to be matched
        String stringToBeMatched
            = "GFG FGF GFG";

        // Create a matcher for the input String
        Matcher matcher
            = pattern
                  .matcher(stringToBeMatched);

        // Get the current matcher state
        MatchResult result
            = matcher.toMatchResult();
        System.out.println("Current Matcher: "
                           + result);

        while (matcher.find()) {
            // Get the group matched using group() method
            System.out.println(matcher.group("GFG"));
        }
    }
}

Output:

Current Matcher: java.util.regex.Matcher[pattern=\b(?[A-Za-z\s]+) region=0,11 lastmatch=]
GFG FGF GFG

Reference: Oracle Doc