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BUG: DataFrame constructor fails when columns is set and data=[] #9939

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BUG: DataFrame constructor fails when columns is set and data=[] #9939

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BUG: DataFrame constructor fails when columns is set and data=[]
evanpw Apr 19, 2015
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evanpw Apr 19, 2015
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1 change: 1 addition & 0 deletions doc/source/whatsnew/v0.16.1.txt
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Expand Up @@ -164,3 +164,4 @@ Bug Fixes

- Fixed latex output for multi-indexed dataframes (:issue:`9778`)
- Bug causing an exception when setting an empty range using ``DataFrame.loc`` (:issue:`9596`)
- Bug in ``DataFrame`` constructor when ``columns`` parameter is set, and ``data`` is an empty list (:issue:`9939`)
3 changes: 1 addition & 2 deletions pandas/core/frame.py
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Expand Up @@ -265,8 +265,7 @@ def __init__(self, data=None, index=None, columns=None, dtype=None,
mgr = self._init_ndarray(data, index, columns, dtype=dtype,
copy=copy)
else:
mgr = self._init_ndarray(data, index, columns, dtype=dtype,
copy=copy)
mgr = self._init_dict({}, index, columns, dtype=dtype)
elif isinstance(data, collections.Iterator):
raise TypeError("data argument can't be an iterator")
else:
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13 changes: 13 additions & 0 deletions pandas/tests/test_frame.py
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Expand Up @@ -3135,6 +3135,19 @@ def test_constructor_empty_list(self):
expected = DataFrame(index=[])
assert_frame_equal(df, expected)

# GH 9939
df = DataFrame([], columns=['A', 'B'])
expected = DataFrame({}, columns=['A', 'B'])
assert_frame_equal(df, expected)

# Empty generator: list(empty_gen()) == []
def empty_gen():
return
yield

df = DataFrame(empty_gen(), columns=['A', 'B'])
assert_frame_equal(df, expected)

def test_constructor_list_of_lists(self):
# GH #484
l = [[1, 'a'], [2, 'b']]
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