Question

I am a java noob and I have particular problem.
Let us consider a String which multipe repetition of alphabets in it :

String a="AAABBBAACCBBDD"

I have tried this multiple times with for and charAt.
Expected output:

"ABCD"

Is there any builtin function for this operation and any ideas to get output ?

Answer 1

I would do something like

public static String dedup(String text) {
    Set<Character> seen = new LinkedHashSet<Character>();
    StringBuilder sb = new StringBuilder();
    for (char c : text.toCharArray())
        if (seen.add(c))
            sb.append(c);
    return sb.toString();
}