Closed
Description
Calling symmetric_difference on two equal multiindices results in a TypeError rather than an empty MultiIndex. This is surprising since calling difference on the same multiindices results in the expected empty MultiIndex.
Code Sample, a copy-pastable example if possible
a = pandas.MultiIndex.from_product([['a', 'b'], [0, 1]])
b = pandas.MultiIndex.from_product([['a', 'b'], [0, 1]])
print(a.symmetric_difference(b))
Which gives the following error:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Miniconda3\envs\balancedbeta\lib\site-packages\pandas\indexes\base.py", line 1674, in __xor__
return self.symmetric_difference(other)
File "C:\Miniconda3\envs\balancedbeta\lib\site-packages\pandas\indexes\base.py", line 1911, in symmetric_difference
return self._shallow_copy_with_infer(the_diff, **attribs)
File "C:\Miniconda3\envs\balancedbeta\lib\site-packages\pandas\indexes\multi.py", line 387, in _shallow_copy_with_infer
return self._shallow_copy(values, **kwargs)
File "C:\Miniconda3\envs\balancedbeta\lib\site-packages\pandas\indexes\multi.py", line 396, in _shallow_copy
return MultiIndex.from_tuples(values, **kwargs)
File "C:\Miniconda3\envs\balancedbeta\lib\site-packages\pandas\indexes\multi.py", line 883, in from_tuples
raise TypeError('Cannot infer number of levels from empty list')
TypeError: Cannot infer number of levels from empty list
Expected Output
MultiIndex(levels=[[], []], labels = [[], []])
output of pd.show_versions()
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 61 Stepping 4, GenuineIntel
byteorder: little
LC_ALL: None
LANG: DA
pandas: 0.18.1
nose: None
pip: 8.1.1
setuptools: 20.7.0
Cython: 0.23
numpy: 1.10.4
scipy: 0.17.0
statsmodels: 0.6.1
xarray: None
IPython: 4.2.0
sphinx: None
patsy: 0.4.1
dateutil: 2.5.2
pytz: 2016.3
blosc: None
bottleneck: None
tables: 3.2.2
numexpr: 2.5.2
matplotlib: 1.5.1
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.12
pymysql: None
psycopg2: None
jinja2: 2.8
boto: None
pandas_datareader: None