Get index of lines that match my linq

Question

I have a linq statement and I would like to know if it is possible to get indicies of lines that match my statement? Here it is:

var result = list3.Where(middle          


        

Answer 1

Also note that if you want to search for the indicies of items matching a predicate very often, it could be worth writing a very simple extension method:

public static class IEnumerableExt
{
    public static IEnumerable FindIndices(this IEnumerable self, Predicate predicate)
    {
        int i = 0;

        foreach (var element in self)
        {
            if (predicate(element))
                yield return i;

            ++i;
        }
    }
}

Which you would call like this:

var result = list3.FindIndices(x => list4.Any(xx => xx == x.middle.Middle.category1));