BUG: Fixed assign failure when with Copy-on-Write #60941
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Since there has been no feedback for two weeks, just a friendly ping @mroeschke @rhshadrach @WillAyd , thanks 🙏 |
pandas/tests/indexing/test_iloc.py
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| # Check that view is modified correctly | ||
| expected_view = DataFrame( | ||
| {"B": [2, 2, 2, 2], "C": [3, 2, 1, 2]}, index=df.index | ||
| ) | ||
| tm.assert_frame_equal(df, expected_view) |
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Nit: Once the assignment is done, this is no longer a view. Can you change to just "df" instead of "view".
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Sure, sovled in fcffbf2
doc/source/whatsnew/v2.3.0.rst
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| @@ -37,6 +37,7 @@ Other enhancements | |||
| updated to work correctly with NumPy >= 2 (:issue:`57739`) | |||
| - :meth:`Series.str.decode` result now has ``StringDtype`` when ``future.infer_string`` is True (:issue:`60709`) | |||
| - :meth:`~Series.to_hdf` and :meth:`~DataFrame.to_hdf` now round-trip with ``StringDtype`` (:issue:`60663`) | |||
| - The :meth:`DataFrame.iloc` now works correctly with ``copy_on_write`` option (:issue:`60309`) | |||
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Can you give a little more detail here. Perhaps adding
after subsetting the columns of a DataFrame and using a slice
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Sure, Solved in 725b41b
| if isinstance(indexer[1], slice) and indexer[1] == slice(None): | ||
| col_indexer = slice(None) | ||
| else: | ||
| col_indexer = np.arange(len(blk_loc)) | ||
| self.blocks[0].setitem((indexer[0], col_indexer), value) |
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It's not clear to me why it's correct to pass through slice(None) but not other cases, e.g. slice(0, 3, 2) or [0, 1].
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I think you're right. My current changes failed under the following test case. I'll mark the PR as a draft until I properly handle the bug and will also add more test cases. Thanks!
dftest3 = pd.DataFrame(
{"A": [1, 4, 1, 5], "B": [2, 5, 2, 6], "C": [3, 6, 1, 7], "D": [8, 9, 10, 11]}
)
df3 = dftest3[["B", "C", "D"]]
df3.iloc[[1, 3], 0:3:2] = [[2, 2], [2, 2]]
doc/source/whatsnew/v2.3.0.rstfile if fixing a bug or adding a new feature.