Re:Friends don't let friends export to CSV
by nradov on Monday March 25, 2024 @07:35PM
(#39822522)
If both parties implement RFC 4180 and use a consistent character set encoding then I don't think there are actually any undefined behaviors. But in practice a lot of implementations are simply broken, including those from major tech companies that ought to know better.
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I don't think RFC 4180 differentiates between an empty string and a null value. As long as you add a check that all string columns are free of empty values before writing you should be good.
I think in polars it's
df.filter(pl.col(pl.Utf8).str.len_bytes() == 0).shape[0] == 0
Well I would consider differentiation between empty string versus null as simply being out of scope for CSV rather than undefined behavior. It was never intended as a complete database dump format.
And the application doesn't try to convert the cells into non-string data types like numbers, dates, etc.
Converting strings into other data types is out of scope for CSV, not really undefined behavior. The type conversions happen at a later stage of the import process.