variables.dropna(subset=['cigarette_smokers', 'birth_wt_child', 'oxygen', 'length_of_stay', 'hospitalized_vitamin_d', 'breastfed']) --------------------------------------------------------------------------- ValueError Traceback (most recent call last) <ipython-input-168-96be0b0b00e8> in <module>() 1 variables.dropna(subset=['cigarette_smokers', 'birth_wt_child', ----> 2 'oxygen', 'length_of_stay', 'hospitalized_vitamin_d', 'breastfed']) /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/frame.pyc in dropna(self, axis, how, thresh, subset, inplace) 2407 if subset is not None: 2408 agg_axis_name = self._get_axis_name(agg_axis) -> 2409 agg_obj = self.reindex(**{agg_axis_name: subset}) 2410 2411 count = agg_obj.count(axis=agg_axis) /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/frame.pyc in reindex(self, index, columns, **kwargs) 2160 def reindex(self, index=None, columns=None, **kwargs): 2161 return super(DataFrame, self).reindex(index=index, columns=columns, -> 2162 **kwargs) 2163 2164 @Appender(_shared_docs['reindex_axis'] % _shared_doc_kwargs) /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/generic.pyc in reindex(self, *args, **kwargs) 1561 return self._reindex_axes(axes, level, limit, 1562 method, fill_value, copy, -> 1563 takeable=takeable).__finalize__(self) 1564 1565 def _reindex_axes(self, axes, level, limit, method, fill_value, copy, /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/frame.pyc in _reindex_axes(self, axes, level, limit, method, fill_value, copy, takeable) 2110 if columns is not None: 2111 frame = frame._reindex_columns(columns, copy, level, fill_value, -> 2112 limit, takeable=takeable) 2113 2114 index = axes['index'] /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/frame.pyc in _reindex_columns(self, new_columns, copy, level, fill_value, limit, takeable) 2137 return self._reindex_with_indexers({1: [new_columns, indexer]}, 2138 copy=copy, fill_value=fill_value, -> 2139 allow_dups=takeable) 2140 2141 def _reindex_multi(self, axes, copy, fill_value): /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/generic.pyc in _reindex_with_indexers(self, reindexers, method, fill_value, limit, copy, allow_dups) 1687 new_data = new_data.reindex_indexer(index, indexer, axis=baxis, 1688 fill_value=fill_value, -> 1689 allow_dups=allow_dups) 1690 1691 elif (baxis == 0 and index is not None and /Library/Python/2.7/site-packages/pandas-0.13.0_395_gef55e60-py2.7-macosx-10.9-intel.egg/pandas/core/internals.pyc in reindex_indexer(self, new_axis, indexer, axis, fill_value, allow_dups) 3227 # trying to reindex on an axis with duplicates 3228 if not allow_dups and not self.axes[axis].is_unique: -> 3229 raise ValueError("cannot reindex from a duplicate axis") 3230 3231 if not self.is_consolidated(): ValueError: cannot reindex from a duplicate axis