SymDate—and I admit the name might be a sloppy inversion—I think the date actually comes first—is merely a concatenated key I use further back upstream to aggregate certain data points on for Symbol + the date I am assessing. To get the data I need from the ‘special’ dictionary, I merely HARD CODE in the 3 special symbols to create the lookup key knowing I have and entry for all 3 EVERY day. So there is a ‘Symdate’ for ‘Regular Symbol’ + date and also a made out of thin air one for ‘Special Symbol’ + date–designed for that dictionary lookup.
So if nothing more here, I guess I will attempt another direction. That is trying to convert to csv, read that back in, then do the dictionary lookups within that read, creating a new csv with all data. I DO appreciate the help on this and will presume that the dataframe is not apppropriate for what I need to do here.