Question

我正在尝试向现有的多索引数据帧添加新行。当我尝试执行此操作时，出现ValueError：无法处理非唯一的多索引！但是，当我尝试读取相同的索引时，会收到一个KeyError，向我显示该索引不存在（因此应该是唯一的？）。

df.loc[('shntswt_40465_1__22',50.0),variables] = values[:-1]
Traceback (most recent call last):
  File "<pyshell#19>", line 1, in <module>
    df.loc[('shntswt_40465_1__22',50.0),variables] = values[:-1]
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 190, in __setitem__
    self._setitem_with_indexer(indexer, value)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 376, in _setitem_with_indexer
    self.obj._data = self.obj.reindex(labels, axis=i)._data
  File "C:\Python37\lib\site-packages\pandas\util\_decorators.py", line 197, in wrapper
    return func(*args, **kwargs)
  File "C:\Python37\lib\site-packages\pandas\core\frame.py", line 3809, in reindex
    return super(DataFrame, self).reindex(**kwargs)
  File "C:\Python37\lib\site-packages\pandas\core\generic.py", line 4356, in reindex
    fill_value, copy).__finalize__(self)
  File "C:\Python37\lib\site-packages\pandas\core\frame.py", line 3741, in _reindex_axes
    fill_value, limit, tolerance)
  File "C:\Python37\lib\site-packages\pandas\core\frame.py", line 3749, in _reindex_index
    tolerance=tolerance)
  File "C:\Python37\lib\site-packages\pandas\core\indexes\multi.py", line 2227, in reindex
    raise ValueError("cannot handle a non-unique multi-index!")
ValueError: cannot handle a non-unique multi-index!

df.loc[('shntswt_40465_1__22',50.0),variables]
Traceback (most recent call last):
  File "<pyshell#22>", line 1, in <module>
    df.loc[('shntswt_40465_1__22',50.0),variables]
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 1494, in __getitem__
    return self._getitem_tuple(key)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 868, in _getitem_tuple
    return self._getitem_lowerdim(tup)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 969, in _getitem_lowerdim
    return self._getitem_nested_tuple(tup)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 1048, in _getitem_nested_tuple
    obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 1913, in _getitem_axis
    return self._get_label(key, axis=axis)
  File "C:\Python37\lib\site-packages\pandas\core\indexing.py", line 141, in _get_label
    return self.obj._xs(label, axis=axis)
  File "C:\Python37\lib\site-packages\pandas\core\generic.py", line 3583, in xs
    drop_level=drop_level)
  File "C:\Python37\lib\site-packages\pandas\core\indexes\multi.py", line 2542, in get_loc_level
    return partial_selection(key)
  File "C:\Python37\lib\site-packages\pandas\core\indexes\multi.py", line 2532, in partial_selection
    indexer = self.get_loc(key)
  File "C:\Python37\lib\site-packages\pandas\core\indexes\multi.py", line 2418, in get_loc
    raise KeyError(key)
KeyError: ('shntswt_40465_1__22', 50.0)

但是我可以检索并分配给现有行。

df.loc[('trf_91000_91005_1',50.0)]
                        m:R  m:X  m:Z m:phiz
Contingency       Freq                      
trf_91000_91005_1 50.0  NaN  NaN  NaN    NaN

df.loc[('trf_91000_91005_1',50.0),variables] = values[:-1]
df.loc[('trf_91000_91005_1',50.0)]
                            m:R      m:X      m:Z   m:phiz
Contingency       Freq                                    
trf_91000_91005_1 50.0  2.85944  10.5443  10.9252  74.8273

我敢肯定，我之前已经使用.loc创建了新的多索引条目，但是我看不到哪里出了错。

熊猫多索引数据帧问题分配新行（我可以使用.loc吗？）-ValueError和KeyError

0 个答案: