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BUG: Raise KeyError when indexing a Series with MultiIndex #26155

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Merged
merged 17 commits into from
Apr 26, 2019
Merged

BUG: Raise KeyError when indexing a Series with MultiIndex #26155

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1cb75f9
'BUG14885'
ryanreh99 Apr 19, 2019
ff3a81f
Added KeyError Exception for MultiIndexes
ryanreh99 Apr 19, 2019
0369704
added KeyError and Exception blocks
ryanreh99 Apr 19, 2019
2fdacb5
removed unused import statement
ryanreh99 Apr 20, 2019
2c1b85b
shifted KeyError check position
ryanreh99 Apr 20, 2019
0f85550
added tests and fixed if statement
ryanreh99 Apr 20, 2019
51a1a3c
undo testcase change
ryanreh99 Apr 20, 2019
0ee36cd
import statements - linting
ryanreh99 Apr 20, 2019
5e06afe
Added whatsnew note and a DataFrame TestCase
ryanreh99 Apr 21, 2019
32404c5
Merge branch 'master' into my-first-branch
ryanreh99 Apr 21, 2019
467e1e7
removed blank line
ryanreh99 Apr 21, 2019
c7ce861
created new test_function
ryanreh99 Apr 22, 2019
b6ede73
edited whats new
ryanreh99 Apr 22, 2019
ac544af
add full stop
ryanreh99 Apr 23, 2019
de63fbe
minor changes
ryanreh99 Apr 23, 2019
b95ae88
more fixes
ryanreh99 Apr 24, 2019
2309e14
typo
ryanreh99 Apr 24, 2019
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1 change: 1 addition & 0 deletions doc/source/whatsnew/v0.25.0.rst
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Expand Up @@ -327,6 +327,7 @@ Indexing
^^^^^^^^

- Improved exception message when calling :meth:`DataFrame.iloc` with a list of non-numeric objects (:issue:`25753`).
- Bug in :meth:`DataFrame.loc` and :meth:`Series.loc` where KeyError was not raised for a ``MultiIndex``. Now, IndexingError takes precedence over KeyError (:issue:`14885`).
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use double backticks on KeyError; use :class:`MultiIndex` ; maybe something more like

Bug in :meth:DataFrame.loc and :meth:Series.loc where KeyError was not raised for a MultiIndex when the key was longer that the number of levels in the :class:MUutiIndex. (:issue:14885).

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@jreback actually when key is longer than the levels of the multiindex IndexingError: Too many indexers was raised and is still raised. So would this be more proper?

Bug in :meth:`DataFrame.loc` and :meth:`Series.loc` where ``KeyError`` was not raised for a ``MultiIndex`` when the key was less than or equal to the number of levels in the :class:`MultiIndex` (:issue:`14885`).

- Bug in which :meth:`DataFrame.append` produced an erroneous warning indicating that a ``KeyError`` will be thrown in the future when the data to be appended contains new columns (:issue:`22252`).
-

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6 changes: 6 additions & 0 deletions pandas/core/indexing.py
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Expand Up @@ -944,6 +944,12 @@ def _handle_lowerdim_multi_index_axis0(self, tup):
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if (len(tup) == self.obj.index.nlevels
and len(tup) > self.obj.ndim):
raise ek
except Exception as e1:
if isinstance(tup[0], (slice, Index)):
raise IndexingError("Handle elsewhere")
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3 changes: 2 additions & 1 deletion pandas/tests/indexing/multiindex/test_getitem.py
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Expand Up @@ -85,7 +85,8 @@ def test_series_getitem_returns_scalar(
@pytest.mark.parametrize('indexer,expected_error,expected_error_msg', [
(lambda s: s.__getitem__((2000, 3, 4)), KeyError, r"^356L?$"),
(lambda s: s[(2000, 3, 4)], KeyError, r"^356L?$"),
(lambda s: s.loc[(2000, 3, 4)], IndexingError, 'Too many indexers'),
(lambda s: s.loc[(2000, 3, 4)], KeyError, r"^356L?$"),
(lambda s: s.loc[(2000, 3, 4, 5)], IndexingError, 'Too many indexers'),
(lambda s: s.__getitem__(len(s)), IndexError, 'index out of bounds'),
(lambda s: s[len(s)], IndexError, 'index out of bounds'),
(lambda s: s.iloc[len(s)], IndexError,
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11 changes: 11 additions & 0 deletions pandas/tests/indexing/multiindex/test_loc.py
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Expand Up @@ -6,6 +6,7 @@

import pandas as pd
from pandas import DataFrame, Index, MultiIndex, Series
from pandas.core.indexing import IndexingError
from pandas.util import testing as tm


Expand Down Expand Up @@ -130,6 +131,16 @@ def test_loc_multiindex(self):
with pytest.raises(KeyError, match=r"^2L?$"):
mi_int.ix[2]

def test_loc_multiindex_too_many_dims(self):
# GH 14885
s = Series(range(8), index=MultiIndex.from_product(
[['a', 'b'], ['c', 'd'], ['e', 'f']]))

with pytest.raises(KeyError, match=r"^\('a', 'd', 'g'\)$"):
s.loc['a', 'd', 'g']
with pytest.raises(IndexingError, match='Too many indexers'):
s.loc['a', 'd', 'g', 'j']

def test_loc_multiindex_indexer_none(self):

# GH6788
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