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BUG: Bug in slicing a multi-index level with an empty-list (GH8737) #8739

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BUG: Bug in slicing a multi-index level with an empty-list (GH8737) #8739

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2 changes: 1 addition & 1 deletion doc/source/whatsnew/v0.15.1.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -246,7 +246,7 @@ Bug Fixes
- Bug in ``Categorical`` reflected comparison operator raising if the first argument was a numpy array scalar (e.g. np.int64) (:issue:`8658`)
- Bug in Panel indexing with a list-like (:issue:`8710`)
- Compat issue is ``DataFrame.dtypes`` when ``options.mode.use_inf_as_null`` is True (:issue:`8722`)

- Bug in slicing a multi-index level with an empty-list (:issue:`8737`)



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6 changes: 4 additions & 2 deletions pandas/core/index.py
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Expand Up @@ -4147,8 +4147,10 @@ def _convert_indexer(r):

# ignore not founds
continue

ranges.append(reduce(np.logical_or,indexers))
if len(k):
ranges.append(reduce(np.logical_or,indexers))
else:
ranges.append(tuple([]))

elif _is_null_slice(k):
# empty slice
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10 changes: 10 additions & 0 deletions pandas/tests/test_indexing.py
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Expand Up @@ -2133,6 +2133,16 @@ def f():
result = s.loc[idx[:,['foo','bah']]]
assert_series_equal(result,expected)

# GH 8737
# empty indexer
multi_index = pd.MultiIndex.from_product((['foo', 'bar', 'baz'], ['alpha', 'beta']))
df = DataFrame(np.random.randn(5, 6), index=range(5), columns=multi_index)
df = df.sortlevel(0, axis=1)

result = df.loc[:, ([], slice(None))]
expected = DataFrame(index=range(5),columns=multi_index.reindex([])[0])
assert_frame_equal(result, expected)

# regression from < 0.14.0
# GH 7914
df = DataFrame([[np.mean, np.median],['mean','median']],
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