Matcher reset(CharSequence) method in Java with Examples

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The reset(CharSequence input) method of Matcher Class is used to reset this matcher and insert the input String passed as the parameter to this matcher.

Syntax:

public Matcher reset(CharSequence input)

Parameters: This method takes the parameter input which is the String to be inserted into matcher after getting reset.

Return Value: This method returns this Matcher after being reset with this input.

Below examples illustrate the Matcher.reset() method:

Example 1:

// Java code to illustrate reset() method
  
import java.util.regex.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Get the regex to be checked
        String regex = "Geeks";
  
        // 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
        System.out.println("Current Matcher: "
                           + matcher.toMatchResult());
  
        // Reset the Matcher using reset() method
        String newStringToBeMatched
            = "GeeksGeeksGeeks";
        matcher = matcher
                      .reset(newStringToBeMatched);
  
        // Get the current matcher state
        System.out.println("Current Matcher after Reset: "
                           + matcher.toMatchResult());
    }
}

Output:

Current Matcher: java.util.regex.Matcher[pattern=Geeks region=0,13 lastmatch=]Current Matcher after Reset: java.util.regex.Matcher[pattern=Geeks region=0,15 lastmatch=]

Example 2:

// Java code to illustrate reset() method
  
import java.util.regex.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Get the regex to be checked
        String regex = "GFG";
  
        // 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
        System.out.println("Current Matcher: "
                           + matcher.toMatchResult());
  
        // Reset the Matcher using reset() method
        String newStringToBeMatched
            = "GFG means GeeksForGeeks";
        matcher = matcher
                      .reset(newStringToBeMatched);
  
        // Get the current matcher state
        System.out.println("Current Matcher after Reset: "
                           + matcher.toMatchResult());
    }
}

Output:

Current Matcher: java.util.regex.Matcher[pattern=GFG region=0,19 lastmatch=]Current Matcher after Reset: java.util.regex.Matcher[pattern=GFG region=0,23 lastmatch=]

Reference: Oracle Doc