I know it's currently thought as so, but functional programming is not the be-all, end-all paradigm. If you've been around for a while, you'd have seen the ebb and flow a few times already.
No one said it was, but in this use case it's far superior to hand written loops. Virtually all modern programming languages have a functional collections API precisely because of this advantage. If you're still writing loops by hand, in nearly all cases, you're stuck in a less effective procedural programming mindset and have simply stopped updating your skills beyond the basics.
If you've been around for a while, you should have already accepted the benefits of functional programming in the places it's most effective and banished low level procedural programming of loops except in cases where extreme optimization is required. There's no eb and flow here, higher order map/reduce/filter style has been the best way since the 60/70/80's when Lisp and Smalltalk were doing it.
