Returns an IEnumerable of paired input. {1,2,3,4} -> {(1,2), (2,3), (3,4)} Useful in doing things like computing intervals between input elements, while only doing a single pass over the input.

AsSlidingPairs.cs

public static class ExtensionMethods
{
    //given a list {1,2,3,4}, this will return {(1,2), (2,3), (3,4)}
    public static IEnumerable<Tuple<T,T>> AsSlidingPairs<T>(this IEnumerable<T> list)
    {
        if(list == null) throw new ArgumentNullException();
        if(!list.Any())
        {
            yield break;
        }
        var previousItem = list.First();
        foreach(var currentItem in list.Skip(1))
        {
            yield return Tuple.Create(previousItem, currentItem);
            previousItem = currentItem;
        }
    }
}