How to get distinct characters?

Question

I have a code like

string code = \"AABBDDCCRRFF\";

In this code, I want to retrieve only distinct characters

The Output should be l

Answer 1

Just for the hell of it - using a StringBuilder

 string code = "AABBDDCCRRFF";
 StringBuilder sb = new StringBuilder();
 code.Distinct().ToList().ForEach(c => sb.Append(c));
 MessageBox.Show(sb.ToString());