The group(int group) method of Matcher Class is used to get the group index of the match result already done, from the specified group.
Syntax:
public String group(int group)
Parameters: This method takes a parameter group which is the group from which the group index of the matched pattern is required.
Return Value: This method returns the index of the first character matched from the specified group.
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 index.
Below examples illustrate the Matcher.group() method:
Example 1:
// Java code to illustrate group() method import java.util.regex.*; public class GFG { public static void main(String[] args) { // Get the regex to be checked String regex = "(G*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(1)); } } } |
Current Matcher: java.util.regex.Matcher[pattern=(G*s) region=0,13 lastmatch=]
s
s
Example 2:
// Java code to illustrate group() method import java.util.regex.*; public class GFG { public static void main(String[] args) { // Get the regex to be checked String regex = "(G*G)"; // Create a pattern from regex Pattern pattern = Pattern.compile(regex); // Get the String to be matched String stringToBeMatched = "GFGFGFGFGFGFGFGFGFG"; // 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(0)); } } } |
Current Matcher: java.util.regex.Matcher[pattern=(G*G) region=0,19 lastmatch=]
G
G
G
G
G
G
G
G
G
G
Reference: https://docs.oracle.com/javase/9/docs/api/java/util/regex/Matcher.html#group-int-
Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.
