Is yield useful outside of LINQ?

Question

When ever I think I can use the yield keyword, I take a step back and look at how it will impact my project. I always end up returning a collection instead of yeilding becau

Answer 1

Note that with yield, you are iterating over the collection once, but when you build a list, you'll be iterating over it twice.

Take, for example, a filter iterator:

IEnumerator  Filter(this IEnumerator coll, Func func)
{
     foreach(T t in coll)
        if (func(t))  yield return t;
}

Now, you can chain this:

 MyColl.Filter(x=> x.id > 100).Filter(x => x.val < 200).Filter (etc)

You method would be creating (and tossing) three lists. My method iterates over it just once.

Also, when you return a collection, you are forcing a particular implementation on you users. An iterator is more generic.