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$h&jk8^i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdgh&jk8^issh6
Case 2
Input : hjdgh&jk8i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdghjk8i0ssh6
Case 3
Input : hjdgh&j&k8i0ssh6
Expect : hjdghjk8i0ssh6
Output : hjdghjki0ssh6
Anyone please help me to figure out, what is wrong in my code logic ??
use [\\W+]
or "[^a-zA-Z0-9]"
as regex to match any special characters and also use String.replaceAll(regex, String) to replace the spl charecter with an empty string. remember as the first arg of String.replaceAll is a regex you have to escape it with a backslash to treat em as a literal charcter.
String c= "hjdg$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);
Your problem is that the indices returned by match.start()
correspond to the position of the character as it appeared in the original string when you matched it; however, as you rewrite the string c
every time, these indices become incorrect.
The best approach to solve this is to use replaceAll
, for example:
System.out.println(c.replaceAll("[^a-zA-Z0-9]", ""));
You can read the lines and replace all special characters safely this way.
Keep in mind that if you use \\W
you will not replace underscores.
Scanner scan = new Scanner(System.in);
while(scan.hasNextLine()){
System.out.println(scan.nextLine().replaceAll("[^a-zA-Z0-9]", ""));
}
Source: Stackoverflow.com