BUG: Fix Series.sort_values descending & mergesort #28698
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jreback
requested changes
Sep 30, 2019
pandas/tests/series/test_sorting.py
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| @@ -86,6 +86,12 @@ def test_sort_values(self): | |||
| with pytest.raises(ValueError, match=msg): | |||
| s.sort_values(inplace=True) | |||
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| # mergesort and ascending=False | |||
doc/source/whatsnew/v0.25.2.rst
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| @@ -102,6 +102,9 @@ Other | |||
| - Compatibility with Python 3.8 in :meth:`DataFrame.query` (:issue:`27261`) | |||
| - Fix to ensure that tab-completion in an IPython console does not raise | |||
| warnings for deprecated attributes (:issue:`27900`). | |||
| - Bug in :meth:`Series.sort_values` when ``ascending`` is set to ``False`` and | |||
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move to 1.0 this is a non trivial change
has2k1
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Yes that is the case. Now for quicksort, the ascending and descending sort are not guaranteed to be reversed versions of each other. n = 100000
np.random.seed(123)
values = np.random.randint(0, 4, n)
idx = np.arange(n)
s = pd.Series(values, index=idx)
asc = s.sort_values(ascending=True)
desc = s.sort_values(ascending=False)
asc.index.equals(desc.index[::-1]) # False ( without nanargsort it is True)Many tests for |
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@has2k1 can you rebase |
The solution uses the `nargsort` function, which was created to handle in one place the intricacies of sorting. Not adapting Series.sort_values to use may have been an oversight. closes pandas-dev#28697
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Closing as this looks stale, but certainly @has2k1 ping if you'd like to pick back up |
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The solution uses the
nargsortfunction, which was created to handlein one place the intricacies of sorting. Not adapting Series.sort_values
to use may have been an oversight.
black pandasgit diff upstream/master -u -- "*.py" | flake8 --diff