How to select values within a provided index range from a List using LINQ

Question

I am a LINQ newbie trying to use it to acheive the following:

I have a list of ints:-

List intList = new List(new int[]{1,2,3,3         


        

Answer 1

For larger lists, a separate extension method could be more appropriate for performance. I know this isn't necessary for the initial case, but the Linq (to objects) implementation relies on iterating the list, so for large lists this could be (pointlessly) expensive. A simple extension method to achieve this could be:

public static IEnumerable IndexRange(
    this IList source,
    int fromIndex, 
    int toIndex)
{
    int currIndex = fromIndex;
    while (currIndex <= toIndex)
    {
        yield return source[currIndex];
        currIndex++;
    }
}