Closed
Description
Sorry in advance if this was already reported - I searched a bit but didn't know exactly what to search.
In [2]: df = pd.DataFrame(0, index=range(1), columns=pd.MultiIndex.from_product([['a', 'b'], ['c']]))
In [3]: cols = [('a',), ('b',)]
In [4]: df[cols[0]]
Out[4]:
c
0 0
In [5]: df[cols[1]]
Out[5]:
c
0 0
In [6]: df[cols]
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-6-957cf8a677a9> in <module>()
----> 1 df[cols]
/home/pietro/nobackup/repo/pandas/pandas/core/frame.pyc in __getitem__(self, key)
1975 if isinstance(key, (Series, np.ndarray, Index, list)):
1976 # either boolean or fancy integer index
-> 1977 return self._getitem_array(key)
1978 elif isinstance(key, DataFrame):
1979 return self._getitem_frame(key)
/home/pietro/nobackup/repo/pandas/pandas/core/frame.pyc in _getitem_array(self, key)
2019 return self.take(indexer, axis=0, convert=False)
2020 else:
-> 2021 indexer = self.ix._convert_to_indexer(key, axis=1)
2022 return self.take(indexer, axis=1, convert=True)
2023
/home/pietro/nobackup/repo/pandas/pandas/core/indexing.pyc in _convert_to_indexer(self, obj, axis, is_setter)
1203 mask = check == -1
1204 if mask.any():
-> 1205 raise KeyError('%s not in index' % objarr[mask])
1206
1207 return _values_from_object(indexer)
KeyError: "[('a',) ('b',)] not in index"
Notice that df[[c[0] for c in cols]] works just fine... but still we probably want to consider as valid a list of valid keys.