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-