重命名熊猫数据帧列后遇到错误：
B=pd.DataFrame(data=[[1,1,1],[2,2,2]],columns={'A','B','C'})
print(B.loc[0,'B'])
B = B.rename(index=str,columns={'B':'B_B'})
print(B.loc[0,'B_B'])
此代码导致以下输出：
> 1
>Traceback (most recent call last):
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagesIPythoncoreinteractiveshell.py", line 2881, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "<ipython-input-29-6df9197203b9>", line 4, in <module>
print(B.loc[0,'B_B'])
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 1310, in __getitem__
return self._getitem_tuple(key)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 796, in _getitem_tuple
return self._getitem_lowerdim(tup)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 922, in _getitem_lowerdim
section = self._getitem_axis(key, axis=i)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 1482, in _getitem_axis
self._has_valid_type(key, axis)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 1409, in _has_valid_type
key = self._convert_scalar_indexer(key, axis)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandascoreindexing.py", line 196, in _convert_scalar_indexer
return ax._convert_scalar_indexer(key, kind=self.name)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandasindexesbase.py", line 1171, in _convert_scalar_indexer
return self._invalid_indexer('label', key)
File "C:UsersFreieL01AppDataLocalContinuumAnaconda3libsite-packagespandasindexesbase.py", line 1284, in _invalid_indexer
kind=type(key)))
TypeError: cannot do label indexing on <class 'pandas.indexes.base.Index'> with these indexers [0] of <class 'int'>}
重命名似乎改变了我的数据帧对象的类型......
运行df.rename(index=str, ...)会导致数据帧索引类型转换为字符串类型，因此它们将是字符串。您可以通过打印出来来确认这一点。
In [19]: B.index
Out[19]: Index(['0', '1'], dtype='object')
因此，这有效：
In [18]: print(B.loc['0', 'B_B'])
1
如果您不希望这样做，只需在重命名B列时不要传递index属性，如下所示：
B = B.rename(columns={'B':'B_B'})