一、series转化成dataframe
df_expenditure_mean = df.groupby(['Gender', 'name'], as_index=False)['income'].mean()
df_expenditure_mean = pd.DataFrame(df_expenditure_mean)#转化成dataframe格式
df_expenditure_mean.rename(columns={
'income':'收入均值'}, inplace = True)
二、dataframe转化成series