Skip to content

BUG: allow empty multiindex (fixes .isin regression, GH16777) #16782

New issue

Have a question about this project? # for a free GitHub account to open an issue and contact its maintainers and the community.

#

By clicking “#”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? # to your account

Merged
merged 11 commits into from
Jul 7, 2017
Merged

BUG: allow empty multiindex (fixes .isin regression, GH16777) #16782

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
11 commits
Select commit Hold shift + click to select a range
17204a6
BUG: allow empty multiindex (fixes .isin regression, GH16777)
Jun 27, 2017
474ff40
BUG: allow empty multiindex (fixes .isin regression, GH16777)
Jun 27, 2017
64908e8
Replace incorrect use of self._levels with self._names
Jun 27, 2017
76967db
Requested change to whats-new
Jul 6, 2017
c84f0bc
Use names property rather than _names in MultiIndex.isin
Jul 6, 2017
f94d2b4
Revert ability to construct MultiIndex from empty arrays, ensure all …
Jul 6, 2017
fe1e043
Remove empty list checks in MultiIndex.__new__
Jul 6, 2017
b0778f0
Remove empty array check in .from_arrays, falling back to check in __…
Jul 6, 2017
e3d670a
Fix for pep8
Jul 6, 2017
39b544a
Split empty from_tuples test
Jul 6, 2017
94ac6b1
add commit number to test
jreback Jul 7, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions doc/source/whatsnew/v0.20.3.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ Indexing
^^^^^^^^

- Bug in ``Float64Index`` causing an empty array instead of ``None`` to be returned from ``.get(np.nan)`` on a Series whose index did not contain any ``NaN`` s (:issue:`8569`)
- Bug in ``MultiIndex.isin`` causing an error when passing an empty iterable (:issue:`16777`)

I/O
^^^
Expand Down
14 changes: 8 additions & 6 deletions pandas/core/indexes/multi.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1129,10 +1129,11 @@ def from_tuples(cls, tuples, sortorder=None, names=None):
of iterables
"""
if len(tuples) == 0:
# I think this is right? Not quite sure...
raise TypeError('Cannot infer number of levels from empty list')

if isinstance(tuples, (np.ndarray, Index)):
if names is None:
msg = 'Cannot infer number of levels from empty list'
raise TypeError(msg)
arrays = [[]] * len(names)
elif isinstance(tuples, (np.ndarray, Index)):
if isinstance(tuples, Index):
tuples = tuples._values

Expand Down Expand Up @@ -2621,8 +2622,9 @@ def _wrap_joined_index(self, joined, other):
@Appender(Index.isin.__doc__)
def isin(self, values, level=None):
if level is None:
return algos.isin(self.values,
MultiIndex.from_tuples(values).values)
values = MultiIndex.from_tuples(values,
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

you might be able to change this to _ensure_index(values) I think (as its more idiomatic). I also don't think you will need the .values

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

_ensure_index is not meant to support values for a MultiIndex I think:

In [159]: pd.core.indexes.base._ensure_index([(1, 2), (3, 4)])
Out[159]: Index([(1, 2), (3, 4)], dtype='object')

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Not able to address this before 0.20.3

names=self.names).values
return algos.isin(self.values, values)
else:
num = self._get_level_number(level)
levs = self.levels[num]
Expand Down
7 changes: 7 additions & 0 deletions pandas/tests/indexes/test_multi.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1720,6 +1720,13 @@ def test_from_tuples(self):
idx = MultiIndex.from_tuples(((1, 2), (3, 4)), names=['a', 'b'])
assert len(idx) == 2

def test_from_tuples_empty(self):
# GH 16777
result = MultiIndex.from_tuples([], names=['a', 'b'])
expected = MultiIndex.from_arrays(arrays=[[], []],
names=['a', 'b'])
tm.assert_index_equal(result, expected)

def test_argsort(self):
result = self.index.argsort()
expected = self.index.values.argsort()
Expand Down