Issue Regarding Regular Expression

[buntha Choudhary]

I am reading the the regular expression tutorial in Sun java.(http://download.oracle.com/javase/tutorial/essential/regex/bounds.html)
Under Boundary Matchers , 1 scenario is like -

Matcher String = ^dog$
Input String = dog
Expected Result : failed
Actual Result : "dog" starting at index 0 and ending at 3

Why I am not getting the No match found as I am appending space infront the dog string and according to the ^dog$ , string should start with d.

[Raymond Tong]

Where did you get the source code of the sample ? or you made one youself ?
I have tried the RegexTestHarness and I got the expected result.

[buntha Choudhary]

Source Code -

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegularExpSelf {

	public static void main(String[] args) {
	
		while(true){
		
		Scanner scan = new Scanner(System.in);
		System.out.print("Enter The Pattern to Match: ");
		Pattern pattern = Pattern.compile(scan.next());
		
		System.out.print("Enter input string to search: ");
		Matcher matcher = pattern.matcher(scan.next());
		
		
		boolean found = false;
		  while (matcher.find()) {
			  
              System.out.println(" I found the text "+"\""+matcher.group()+"\""+" starting at index "+matcher.start()+
            		  " and ending at "+matcher.end()+ " and group count is "+matcher.groupCount());
              found = true;
          }
          if(!found){
             System.out.println("No Matcher Found");
          }
		
	}

	}

}

[Raymond Tong]

buntha Choudhary wrote:Source Code -

		Matcher matcher = pattern.matcher(scan.next());

Try to print the content of scan.next() before passing to the matcher method

[Gaurav Sainii]

@buntha: the code you provided is working fine by passing the specified pattern.

Though you can try hardcoding the pattern and then pass the input to test the same.
The code is anyhow still correct and working fine.

[buntha Choudhary]

This issue is coming because scan.text() is trimming the space or it is considering only dog as string even I am providing the space before that.

[Raymond Tong]

buntha Choudhary wrote:This issue is coming because scan.text() is trimming the space or it is considering only dog as string even I am providing the space before that.

Have a look on Scanner in Java API Doc.
You would know why.

[buntha Choudhary]

Thanks to all .