Python df.groupby(a,as_index=False)[‘‘].sum().sort_values(‘‘,ascending=False).reset_index(drop=True)

#as_index=False结果的列名与之前一致
aa=chipo.groupby(['item_name'],as_index=False)['quantity'].sum() 
#大类的销售金额  reset_index(drop=True) 删除原index
daleijine=df.groupby(['大类名称'],as_index=False)['销售金额'].sum().sort_values(['销售金额'],ascending=False).reset_index(drop=True)