Question

Possible Duplicate:
Replacing all non-alphanumeric characters with empty strings

import java.util.Scanner;
import java.util.regex.*;
public class io{
public static void main(String args[]){
Scanner scan = new Scanner(System.in);
String c;
if((c=scan.nextLine())!=null)
 {
Pattern pt = Pattern.compile("[^a-zA-Z0-9]");
Matcher match= pt.matcher(c);
    while(match.find()){
         c=c.replace(Character.toString(c.charAt(match.start())),"");
         }
    System.out.println(c);
      }
   }
}

Case 1

Input : hjdg$h&jk8^i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdgh&jk8^issh6

Case 2

Input : hjdgh&jk8i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdghjk8i0ssh6

Case 3

Input : hjdgh&j&k8i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdghjki0ssh6

Anyone please help me to figure out, what is wrong in my code logic ??

Answer 1

use [\\W+] or "[^a-zA-Z0-9]" as regex to match any special characters and also use String.replaceAll(regex, String) to replace the spl charecter with an empty string. remember as the first arg of String.replaceAll is a regex you have to escape it with a backslash to treat em as a literal charcter.

          String c= "hjdg$h&jk8^i0ssh6";
        Pattern pt = Pattern.compile("[^a-zA-Z0-9]");
        Matcher match= pt.matcher(c);
        while(match.find())
        {
            String s= match.group();
        c=c.replaceAll("\\"+s, "");
        }
        System.out.println(c);