Python Pandas groupby 后 通过index获取值报错KeyErro

学习pandas时，发现通过index获取groupby操作后的数据报错keyerror，大佬们帮忙看下是什么问题

源代码

import pandas as pd
def pd_account(list_agg,list_group,model):
    filename = "datafile/home_account.xlsx"
    df = pd.read_excel(filename)
    df.columns = ['y','m','d','lsfx','lsje','zffs','lslb','bz','fqr']
    list_col = list_group + list_agg
    df = df[list_col]
    group_df = df.groupby(list_group).agg(model)
    print(group_df)
    for item in group_df.index:
        print(item)
        print(group_df[item])
if __name__ == "__main__":
    pd_account(['lsje'],['y','lsfx'],'sum')

print(df)

        y lsfx      lsje
0    2023    +  14334.74
1    2023    -    107.00
..    ...  ...       ...
169  2023    -    461.00
170  2023    +    461.00
171  2023    -     15.80

[172 rows x 3 columns]

print(group_df

               lsje
y    lsfx          
2023 +     561520.79
     -     209005.97

遍历index(print(item))结果

===============================
(2023, '+')
(2023, '-')

通过Index获取值报错

C:\Users\MA110\AppData\Local\Programs\Python\Python311\python.exe E:\OneDrive\MyProject\pythonProject_AppAccount\FunAccount.py 
Traceback (most recent call last):
  File "C:\Users\MA110\AppData\Local\Programs\Python\Python311\Lib\site-packages\pandas\core\indexes\base.py", line 3652, in get_loc
    return self._engine.get_loc(casted_key)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "pandas\_libs\index.pyx", line 147, in pandas._libs.index.IndexEngine.get_loc
  File "pandas\_libs\index.pyx", line 176, in pandas._libs.index.IndexEngine.get_loc
  File "pandas\_libs\hashtable_class_helper.pxi", line 7080, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas\_libs\hashtable_class_helper.pxi", line 7088, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: (2023, '+')

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "E:\OneDrive\MyProject\pythonProject_AppAccount\FunAccount.py", line 14, in <module>
    pd_account(['lsje'],['y','lsfx'],'sum')
  File "E:\OneDrive\MyProject\pythonProject_AppAccount\FunAccount.py", line 12, in pd_account
    print(group_df[item])
          ~~~~~~~~^^^^^^
  File "C:\Users\MA110\AppData\Local\Programs\Python\Python311\Lib\site-packages\pandas\core\frame.py", line 3761, in __getitem__
    indexer = self.columns.get_loc(key)
              ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\MA110\AppData\Local\Programs\Python\Python311\Lib\site-packages\pandas\core\indexes\base.py", line 3654, in get_loc
    raise KeyError(key) from err
KeyError: (2023, '+')

进程已结束,退出代码1

你那个print里面的group_df[item]出不来结果，因为item是数字不是列名

在for循环前面，直接输出group_df，看看是个啥

不知道你这个问题是否已经解决, 如果还没有解决的话:

• 这篇博客: pandas中groupby函数中参数ax_index和group_keys的区别中的 五、group_keys的特殊情况 部分也许能够解决你的问题, 你可以仔细阅读以下内容或者直接跳转源博客中阅读:
  

  当调用聚合函数时，其本身的索引会失效，此时传递group_keys=False无效(与group_keys=True一样)
  

如果你已经解决了该问题, 非常希望你能够分享一下解决方案, 写成博客, 将相关链接放在评论区, 以帮助更多的人 ^-^