What is the best practice to use when you need to go through each element in a map and perhaps delete some? I've been using Iterator Class, but noticed that in one of the example project "We don't need repeats" the example uses a copy of the original map and goes through those values and deletes elements form the original. I assume for very large map this is not ideal due to resources use of cloning the original map, but what are advance students thoughts on this? Wht is the best way to go through maps when needing to delete some elements?