Code Sample, a copy-pastable example if possible
In [1]: from pandas import Series, DataFrame
In [2]: class SubclassedSeries(Series):
...:
...: @property
...: def _constructor(self):
...: return SubclassedSeries
...:
...: @property
...: def _constructor_expanddim(self):
...: return SubclassedDataFrame
...:
...: class SubclassedDataFrame(DataFrame):
...:
...: @property
...: def _constructor(self):
...: return SubclassedDataFrame
...:
...: @property
...: def _constructor_sliced(self):
...: return SubclassedSeries
...:
In [3]: sdf = SubclassedDataFrame({"A": [0, 1, 2], "B": [0, 1, 2]})
In [4]: sdf.stack()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-4-987edeff1e47> in <module>()
----> 1 sdf.stack()
~/Software/miniconda3/envs/pandas_stack/lib/python3.6/site-packages/pandas/core/frame.py in stack(self, level, dropna)
4506 return stack_multiple(self, level, dropna=dropna)
4507 else:
-> 4508 return stack(self, level, dropna=dropna)
4509
4510 def unstack(self, level=-1, fill_value=None):
~/Software/miniconda3/envs/pandas_stack/lib/python3.6/site-packages/pandas/core/reshape/reshape.py in stack(frame, level, dropna)
545
546 klass = type(frame)._constructor_sliced
--> 547 return klass(new_values, index=new_index)
548
549
TypeError: 'property' object is not callable
Problem description
When using stack() on a DataFrame into a Series, the code incorrectly references the class rather than the instance. This works for DataFrame as _constructor_sliced is on the class, but using the paradigm defined here it does not work. Should be as simple as changing 546 to klass = frame._constructor_sliced. Seems like this was worked on in #15655 and reported in #15563 but I don't see an associated commit. What's the status @delgadom?
Expected Output
In [5]: sdf = SubclassedDataFrame({"A": [0, 1, 2], "B": [0, 1, 2]})
In [6]: sdf.stack()
Out[6]:
0 A 0
B 0
1 A 1
B 1
2 A 2
B 2
dtype: int64
Output of pd.show_versions()
[paste the output of ``pd.show_versions()`` here below this line]
INSTALLED VERSIONS
------------------
commit: None
python: 3.6.2.final.0
python-bits: 64
OS: Linux
OS-release: 3.16.0-38-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
pandas: 0.21.1
pytest: None
pip: 9.0.1
setuptools: 36.4.0
Cython: None
numpy: 1.13.1
scipy: None
pyarrow: None
xarray: None
IPython: 6.1.0
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: None
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
Comment From: jreback
duplicate of #15563
if you want to take up #15655 would be great.