This is part of some Pandas code I wrote a while back. No doubt it seemed perfectly reasonable at the time. But I didn't comment it, and searching is proving frustrating and unproductive.
Looks liks this this reverse the order of the rows. But I'm fuzzy as to why.
I need a good explanation (references are a plus) on Python's slice notation.
To me, this notation needs a bit of picking up.
It looks extremely powerful, but I haven't quite got my head around it.