Problem after groupby (pandas), the grouped column is not accessible - pandas

Question

I have a problem after groupby and receive this error message:
Traceback (most recent call last):
File "C:\Users\User\PycharmProjects\HashTag_Curso\venv\lib\site-packages\pandas\core\indexes\base.py", line 3080, in get_loc
return self._engine.get_loc(casted_key)
File "pandas_libs\index.pyx", line 70, in pandas._libs.index.IndexEngine.get_loc
File "pandas_libs\index.pyx", line 101, in pandas._libs.index.IndexEngine.get_loc
File "pandas_libs\hashtable_class_helper.pxi", line 4554, in pandas._libs.hashtable.PyObjectHashTable.get_item
File "pandas_libs\hashtable_class_helper.pxi", line 4562, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'Ano'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:/Users/User/PycharmProjects/Bibliotecas/Exemplo.py", line 11, in
x = dfg['Ano']
File "C:\Users\User\PycharmProjects\HashTag_Curso\venv\lib\site-packages\pandas\core\frame.py", line 3024, in getitem
indexer = self.columns.get_loc(key)
File "C:\Users\User\PycharmProjects\HashTag_Curso\venv\lib\site-packages\pandas\core\indexes\base.py", line 3082, in get_loc
raise KeyError(key) from err
KeyError: 'Ano'
import pandas as pd
from matplotlib import pyplot as plt
import numpy as np
from astropy.stats import biweight_midcorrelation as bw_cor
df = pd.read_csv(r'Bases_dados\D_1_4M\Tudo/combined.csv').iloc[:100000]
df['Ano'] = df['Data decimal']//1
dfg = df.groupby(by=["Ano"]).mean()
print(dfg)
x = dfg['Ano']
y = dfg['Lances']
r = np.corrcoef(x, y)[0][1]
bwr = bw_cor(x, y)
print(bwr, r)
plt.scatter(x, y)
plt.show()
If i use
x = df['Ano']
y = df['Lances']
work fine, but with dfg (grouped by 'Ano'), i receive that err msg.
When i print(dfg), the column "Ano" appears normally.

Answer 1

It's moved to the index part, so you can either reset_index or pass as_index=False to groupby to begin with:
dfg = df.groupby(by="Ano", as_index=False).mean()