Open In App
Related Articles

Matcher start() method in Java with Examples

Improve
Improve
Improve
Like Article
Like
Save Article
Save
Report issue
Report
The start() method of Matcher Class is used to get the start index of the match result already done. Syntax:
public int start()
Parameters: This method do not takes any parameter. Return Value: This method returns the index of the first character matched.0 Exception: This method throws IllegalStateException if no match has yet been attempted, or if the previous match operation failed. Below examples illustrate the Matcher.start() method: Example 1:
// Java code to illustrate start() method
  
import java.util.regex.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Get the regex to be checked
        String regex = "(G*k)";
  
        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);
  
        // Get the String to be matched
        String stringToBeMatched = "Geeks";
  
        // 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 first index of match result
            System.out.println(matcher.start());
        }
    }
}

                    
Output:
Current Matcher: java.util.regex.Matcher[pattern=(G*k) region=0,5 lastmatch=] 3
Example 2:
// Java code to illustrate start() 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 = "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 first index of match result
            System.out.println(matcher.start());
        }
    }
}

                    
Output:
Current Matcher: java.util.regex.Matcher[pattern=(G*G) region=0,3 lastmatch=] 0 2
Reference: Oracle Doc

Last Updated : 26 Nov, 2018
Like Article
Save Article
Previous
Next
Share your thoughts in the comments
Similar Reads