How to Dereference a Filter Iterator

When you call begin on this iterator that or when you do reference call to the user, it's going to go and iterate through the elements. Instead of doing the find if when you decrement the iteration, you could instead do the find if whenever you call begin. And there's also this like whole thing where like you can cache the results so that,. because obviously if you decrement a filter view twice, you don't want to do that find if twice.