@kellerfuchs Nice!
And I'm relatively language agnostic for getting things like that done. I think the fastest language for proper data munging is like perl or something?
R needs a lot of handholding to get vectorisation running, but it does suck with RAM stuff. If you ever look up its garbage collection scheme you're gonna be unhappy!
I've done data pushing together with Rust in the past, that seems to work quite nicely because I can control RAM use a lot more finely.