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Merged
merged 4 commits into from
Apr 12, 2019
Merged

Indexing with an empty array #2883

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2e1c06b
Indexing with an empty array
mdavezac Apr 10, 2019
abc4b38
Adds 2882 resolution to whats-new.rst
mdavezac Apr 10, 2019
5412729
Create empty indexing array directly
mdavezac Apr 11, 2019
cf0052f
assert xxx -> asset_identical
mdavezac Apr 11, 2019
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3 changes: 3 additions & 0 deletions doc/whats-new.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,9 @@ Enhancements
Bug fixes
~~~~~~~~~

- indexing with an empty list creates an object with zero-length axis (:issue:`2882`)
By `Mayeul d'Avezac <https://github.com/mdavezac>`_.

.. _whats-new.0.12.1:

v0.12.1 (4 April 2019)
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4 changes: 3 additions & 1 deletion xarray/core/dataset.py
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Expand Up @@ -8,7 +8,7 @@
from distutils.version import LooseVersion
from numbers import Number
from typing import (
Any, Callable, Dict, List, Optional, Set, Tuple, TypeVar, Union)
Any, Callable, Dict, List, Optional, Set, Tuple, TypeVar, Union, Sequence)

import numpy as np
import pandas as pd
Expand Down Expand Up @@ -1516,6 +1516,8 @@ def _validate_indexers(
v = as_variable(v)
elif isinstance(v, Dataset):
raise TypeError('cannot use a Dataset as an indexer')
elif isinstance(v, Sequence) and len(v) == 0:
v = IndexVariable((k, ), np.zeros((0,), dtype='int64'))
else:
v = np.asarray(v)

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8 changes: 8 additions & 0 deletions xarray/tests/test_dataarray.py
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Expand Up @@ -501,6 +501,14 @@ def test_getitem_dataarray(self):
assert_equal(da[ind], da[[0, 1]])
assert_equal(da[ind], da[ind.values])

def test_getitem_empty_index(self):
da = DataArray(np.arange(12).reshape((3, 4)), dims=['x', 'y'])
assert_identical(da[{'x': []}],
DataArray(np.zeros((0, 4)), dims=['x', 'y']))
assert_identical(da.loc[{'y': []}],
DataArray(np.zeros((3, 0)), dims=['x', 'y']))
assert_identical(da[[]], DataArray(np.zeros((0, 4)), dims=['x', 'y']))

def test_setitem(self):
# basic indexing should work as numpy's indexing
tuples = [(0, 0), (0, slice(None, None)),
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