Question

What is the most elegant way to return a string from a List
ok, yeah, I know I can do something like

public string Convert(List<int> something)
{
    var s = new StringBuilder();
    foreach(int i in something)
        s.AppendFormat("{0} ", i);

    return s.ToString();
}

but i m sure there is a way to do this with lambdas
I tried also to append to a stringbuilder but that is not doing whats expected

Answer 1

IMO, you were better off with your original version; LINQ is great, but it isn’t the answer to every problem. In particular, the string.Join approach demands an extra array (for little gain), and the Aggregate approach uses lots of intermediate strings.

Perhaps make it an extension method, though – and lose the Format stuff:

public static string Concatenate<T>(this IEnumerable<T> source, string delimiter)
{
   var s= new StringBuilder();
   bool first = true;
   foreach(T t in source) {
      if(first) {
        first = false;
      } else {
        s.Append(delimiter);
      }
      s.Append(t);
   }    
   return s.ToString();
}