How would I remove letters at an even position throughout a string in Java?

Question

        
        String evensRemoved = "";
        
        String str = reversedNames[1];
        
        String noSpaces = str.replace(" ","");
        
        int strlength = noSpaces.length();
        
        for(int i = 0; i <= strlength; i++){
            
            if(i % 2 == 0){
                StringBuilder sb = new StringBuilder(noSpaces);
                sb.deleteCharAt(i);
                
                String result = sb.toString();
                
                return result;
            }
        }
        
        return "";

I want to be able to remove letters at even positions throughout the string completely, and then return the string to the original method. I've looked at other solutions and haven't been able to figure it out at all. New to Java.

Answer 1

Try this.

• It uses a regex that takes two chars at a time and replaces them with the 2nd, thus removing every other one.
• the (.) is a capture group of 1 character.
• $1 is a back reference to it.

   String s = "abcdefghijklmnopqrstuvwxyz";
   s = s.replaceAll("(?s).(.)?", "$1");
   System.out.println(s);

Prints

bdfhjlnprtvxz

per Andreas suggestion, I preceded the regex with a flag that lets . match returns and linefeeds.