What is the most elegant way to get a set of items by index from a collection?

Question

Given

IList indexes;
ICollection collection;

What is the most elegant way to extract all T in

Answer 1

You could do it in an extension method:

static IEnumerable Extract(this ICollection collection, IList indexes)
{
   int index = 0;
   foreach(var item in collection)
   {
     if (indexes.Contains(index))
       yield item;
     index++;
   }
}