BUG: 0/0 with arrow backend is not "NA"

[b-phi]

BUG: 0/0 with arrow backend is not "NA"

[asishm]

xref #32265. See also #58988 and the comment chain https://github.com/pandas-dev/pandas/pull/58988/files#r1636855759

I wouldnt consider float64, Float64 and double[pyarrow] as the same dtype but different backends in the current state of pandas (there is a separate PDEP out there that talks about creating unified pandas dtypes)

[WillAyd]

Yes technically even going back to IEEE 757 0/0 is NaN; the Float64 data type does not consider NaN to be a missing value (i.e. NA)

What you expect is reasonable given the history of pandas, but the future of it is uncertain. @asishm has linked the proper discussion; I think in the long term the behavior of the OP is correct but we are just missing a isnan method if you truly cared to detect NaN

[b-phi]

Thank you for the discussion links. Some way to detect the nan beyond np.isnan(df) would certainly cover our use case. The discrepancy between series.isna() and series.apply(pd.isna) is also quite confusing.

[MarcoGorelli]

thanks for the report!

this looks like the topic of conversation in #32265, so I'm going to close in favour of that