Python 从数据帧中 Select 变量S类别

我使用的是pythonseborn库的TIPS数据集.我正在根据"时间"变量的类别(晚餐和午餐)找出"TOTAL_BILL"的总和、最小值、最大值和平均值.

df = sns.load_dataset("tips")
df.head()

   total_bill   tip     sex smoker  day    time  size
0       16.99  1.01  Female     No  Sun  Dinner     2
1       10.34  1.66    Male     No  Sun  Dinner     3
2       21.01  3.50    Male     No  Sun  Dinner     3
3       23.68  3.31    Male     No  Sun  Dinner     2
4       24.59  3.61  Female     No  Sun  Dinner     4

df.groupby(["time"]).agg({"total_bill":["sum","min", "max" ,"mean"]})

这给出了下面的输出.我怎么才能改成只选晚餐呢？

       total_bill                        
              sum   min    max       mean
time                                     
Lunch     1167.47  7.51  43.11  17.168676
Dinner    3660.30  3.07  50.81  20.797159

我试过下面的一个，但它给了我"晚餐"为真，"午餐"为假

df.groupby(df["time"]=="Dinner").agg({"total_bill":["sum","min", "max" ,"mean"]})
     

                 total_bill                        
             sum   min    max       mean
time                                    
False    1167.47  7.51  43.11  17.168676
True     3660.30  3.07  50.81  20.797159