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BUG: Fix Index construction when given empty generator (#21470). #21481

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Merged
merged 8 commits into from
Jun 18, 2018
+21 −16
Merged

BUG: Fix Index construction when given empty generator (#21470). #21481

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662eea2
BUG: Fix Index construction when given empty generator (#21470).
Liam3851 Jun 14, 2018
e470745
Fix trailing whitespace
Liam3851 Jun 14, 2018
bf81721
Don't nest if statements.
Liam3851 Jun 14, 2018
b0d9d2a
Fix CategoricalIndex constructor with iterator; test empty iterators.
Liam3851 Jun 14, 2018
254676c
Remove unused import.
Liam3851 Jun 15, 2018
ad2c0cb
Add whatsnew.
Liam3851 Jun 15, 2018
b2cf81f
Merge branch 'master' into PR_TOOL_MERGE_PR_21481
jreback Jun 18, 2018
650f810
doc
jreback Jun 18, 2018
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10 changes: 6 additions & 4 deletions pandas/core/indexes/base.py
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Original file line number Diff line number Diff line change
Expand Up @@ -430,12 +430,14 @@ def __new__(cls, data=None, dtype=None, copy=False, name=None,
elif data is None or is_scalar(data):
cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data) and data:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
# we must be all tuples, otherwise don't construct
# 10697
if all(isinstance(e, tuple) for e in data):

if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from .multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get('names'))
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10 changes: 9 additions & 1 deletion pandas/tests/indexes/test_base.py
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Expand Up @@ -445,14 +445,22 @@ def test_constructor_dtypes_timedelta(self, attr, klass):
result = klass(list(values), dtype=dtype)
tm.assert_index_equal(result, index)

def test_constructor_empty_gen(self):
def test_constructor_empty_list(self):
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@mroeschke mroeschke Jun 14, 2018 •
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Could you combine this test with the one below with pytest.mark.parametrize over skip_index_keys and the empty list and generator?

skip_index_keys = ["repeats", "periodIndex", "rangeIndex",
"tuples"]
for key, index in self.generate_index_types(skip_index_keys):
empty = index.__class__([])
assert isinstance(empty, index.__class__)
assert not len(empty)

def test_constructor_empty_gen(self):
skip_index_keys = ["repeats", "periodIndex", "rangeIndex",
"tuples"]
for key, index in self.generate_index_types(skip_index_keys):
empty = index.__class__(x for x in [])
assert isinstance(empty, index.__class__)
assert not len(empty)

@pytest.mark.parametrize("empty,klass", [
(PeriodIndex([], freq='B'), PeriodIndex),
(RangeIndex(step=1), pd.RangeIndex),
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