God I hate csv with the fire of a thousand suns.

Contractors never seem to know how to write them correctly. Last year, one even provided “csv”s that were just Oracle error messages. lol. Another told me their system could not quote string columns nor escape commas or use anything but commas as their separator, so there were unpredictable numbers of commas in the rows when the actual data contained commas. Total nightmare. And so much of my data has special character issues because somewhere in the pipeline a text encoding was wrong and there is exactly one mangled character in 5 million lines for me to find.

Give me the data as closely to the source data as you can. If it is a database, then a database dump or access to a clone of your database is the best option by far. I don’t care how obscure your shit is, Ill do the conversion myself.

For intermediate data, something like parquet or language specific formats like Rdata or pickle files. Maaaaybe very carefully created csv files for archival purposes, but even then, I think parquet is safe for the long haul nowadays.