While R isn't my favorite language of the ones I regularly use, I know you #rstats people adore it, so here's a fun package you should try out:

https://github.com/dirkschumacher/transduceR

If you like functional style, but want efficiency too, try out transducers, they're an amazing little tool that I'm still picking up, but they give you pipelines that don't create intermediate arrays (and composable reductions, lazy evaluation in this case, etc). Thus, they still provide clean, familiar functional syntax but with a pretty sizable performance boost!

Here's a conceptual primer on them from Clojure as well:

https://clojure.org/reference/transducers

I hope this proves useful to some of you! 😁