Jonathon Bolster

The original intention for this was to clean up some code which was calling a Select to get an Index value so that basic zebra striping of rows could be done. It return an IndexedType generic class of type T which has properties for the original object and the index value of it.

public static IEnumerable<IndexedType<T>> Index<T>(this IEnumerable<T> source)
{
	return source.Select((x, i) => new IndexedType<T>() { Item = x, Index = i });
}

And the class returned:

public class IndexedType<T>
{
	public T Item { get; set; }
	public int Index { get; set; }
}

This could be extended to include values like if the index value is even, N-Indexed values, etc but I leave that up to the imagination of the programmer.

This is yet another extension.

I don’t like Enumerable.Range() for the sole reason you have to give a start index and a count. So I made up my own. This is an extension for an integer type and will allow you to specify two values that you want a range for

public static IEnumerable<int> RangeTo(this int startValue, int endValue, int step)
{
	return (endValue < startValue) ?
		Enumerable.Range(endValue, startValue - endValue + 1).Reverse() :
		Enumerable.Range(startValue, endValue - startValue + 1);
}

This will also allow for reverse lists – see how to use it below:

1.RangeTo(10);  // {1,2,3,4,5,6,7,8,9,10}
5.RangeTo(10);  // {5,6,7,8,9,10}
10.RangeTo(5);  // {10,9,8,7,6,5}
3.RangeTo(3);   // {3}

int x = 15;
int y = 17;
x.RangeTo(10);  // {15,14,13,12,11,10}
y.RangeTo(x);  // {17,16,15}
x.RangeTo(y);  // {15,16,17}
13.RangeTo(x); // {13,14,15}