ENH: Allow convert_dtypes to convert to pd.ArrowDtype #50094
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mroeschke
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Enhancement
Dtype Conversions
jrbourbeau
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jrbourbeau
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Nice @mroeschke!
I definitely think the io.nullable_backend -> mode.nullable_backend change makes sense given it's being generalized outside of just read_* I/O functions.
| def test_pyarrow_nullable_backend_already_pyarrow(self): | ||
| pytest.importorskip("pyarrow") | ||
| expected = pd.DataFrame([1, 2, 3], dtype="int64[pyarrow]") | ||
| with pd.option_context("mode.nullable_backend", "pyarrow"): | ||
| result = expected.convert_dtypes() | ||
| tm.assert_frame_equal(result, expected) |
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Does setting mode.nullable_backend to "pyarrow" work when the original dtypes are already numpy-backed extension dtypes? For example, something like
expected = pd.DataFrame([1, 2, 3], dtype="Int64")
with pd.option_context("mode.nullable_backend", "pyarrow"):
result = expected.convert_dtypes()
tm.assert_frame_equal(result, expected)or adding a df.convert_dtypes() line before with pd.option_context("mode.nullable_backend", "pyarrow"): in test_pyarrow_nullable_backend
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Yup this should convert the numpy-backed types to pyarrow-backed types. Will add a unit test for it
| infer_objects : bool, defaults False | ||
| Whether to also infer objects to float/int if possible. Is only hit if the | ||
| object array contains pd.NA. | ||
| nullable_backend : str, default "pandas" |
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How does this interact with the mode.nullable_backend option? My guess is folks would expect nullable_backend to take precedent if it's specified, but for mode.nullable_backend to take precedent if nullable_backend isn't given.
Here's a tiny example of the use case where I'm asking what happens:
with pd.option_context("mode.nullable_backend", "pyarrow"):
result = expected.convert_dtypes(nullable_backend="pandas")There was a problem hiding this comment.
This line specifically is a private helper function that backs the public Series/DataFrame.convert_dtypes.
The public Series/DataFrame.convert_dtypes will not accept a keyword argument nullable_backend
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Ah, I see -- thanks for clarifying. So the nullable_backend config option is how public APIs toggle here. Good to know.
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convert_dtypesto convert topd.ArrowDtype#49997 (Replace xxxx with the GitHub issue number)doc/source/whatsnew/vX.X.X.rstfile if fixing a bug or adding a new feature.Additionally changed
io.nullable_backendtomode.nullable_backendto make it more general