How do I add two lists in Linq so addedList[x] = listOne[x] + listTwo[x]?

Question

I want to add two lists of a numeric type such that addedList[x] = listOne[x] + listTwo[x]

The output of the list needs to be a Generic.IEnumerable that I can use i

Answer 1

What you're looking for is a Zip method. This method allows you to combine to lists of equal length into a single list by applying a projection.

For example

var sumList = firstList.Zip(secondList, (x,y) => x + y).ToList();

This method was added to the BCL in CLR 4.0 (Reference). It's fairly straight forward to implement though and many versions are available online that can be copied into a 2.0 or 3.5 application.