Fix inconsistent results for empty datasets describe #41716
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weikhor
changed the title
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this currently fails on master right? |
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Hello @weikhor! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:
Comment last updated at 2021-06-08 16:24:04 UTC |
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This pull request is stale because it has been open for thirty days with no activity. Please update or respond to this comment if you're still interested in working on this. |
| @@ -675,7 +682,7 @@ def nunique(self, dropna: bool = True) -> Series: | |||
| @doc(Series.describe) | |||
| def describe(self, **kwargs): | |||
| result = self.apply(lambda x: x.describe(**kwargs)) | |||
| if self.axis == 1: | |||
| if self.axis == 1 or not isinstance(result.index, MultiIndex): | |||
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As @jreback commented, can check that it's not empty. I think the code would be more readable if we added it as a separate check without the transpose - I couldn't figure out why you'd want to take the transpose before realizing the frame is empty.
if result.empty:
return result
elif self.axis == 1:
return result.T
| @@ -1850,4 +1861,4 @@ def func(df): | |||
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| return self._python_apply_general(func, self._obj_with_exclusions) | |||
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| boxplot = boxplot_frame_groupby | |||
| boxplot = boxplot_frame_groupby | |||
| @@ -1206,3 +1206,10 @@ def test_groupby_sum_below_mincount_nullable_integer(): | |||
| result = grouped.sum(min_count=2) | |||
| expected = DataFrame({"b": [pd.NA] * 3, "c": [pd.NA] * 3}, dtype="Int64", index=idx) | |||
| tm.assert_frame_equal(result, expected) | |||
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| def test_groupby_empty_dataset(): | |||
| # 41575 | |||
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Can you prefix with GH or GH # or GH#? We're not consistent, but I believe there is usually some prefix.
| def test_groupby_empty_dataset(): | ||
| # 41575 | ||
| df = DataFrame(columns=["A", "B", "C"]) | ||
| result = df.groupby("A").B.describe().reset_index(drop=True) |
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Can you remove the reset index? The test should just test the behavior of describe.
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Thanks for the PR, but it appears that this has gone stale and needs to address the reviews. Closing due to inactivity but happy to reopen if you're interested in continuing. |
GroupBy.describeproduces inconsistent results for empty datasets #41575