数据框熊猫中分组数据的长度

Question

我在数据框中分组了4个变量。

with pd.option_context('display.max_rows', None, 'display.max_columns', None): 
     print(df_test[df_test['SLOTID'].isin(['N0CP0.CP','N2CP0.CP','N4CP0.CP','N6CP0.CP' ])][['SLOTID','LANE','Loss','EYE_WIDTH']].groupby(['SLOTID','LANE','Loss','EYE_WIDTH']).agg(list))

  SLOTID    LANE  Loss       EYE_WIDTH
N0CP0.CP  0     10.381169      62.4         [SLOTID, LANE, Loss, EYE_WIDTH]
                10.404240      50.7         [SLOTID, LANE, Loss, EYE_WIDTH]
                               54.6         [SLOTID, LANE, Loss, EYE_WIDTH]
                               58.5         [SLOTID, LANE, Loss, EYE_WIDTH]
                               62.4         [SLOTID, LANE, Loss, EYE_WIDTH]
                               66.3         [SLOTID, LANE, Loss, EYE_WIDTH]
                               70.2         [SLOTID, LANE, Loss, EYE_WIDTH]
              1     10.150914  62.4         [SLOTID, LANE, Loss, EYE_WIDTH]
                    10.196356  54.6         [SLOTID, LANE, Loss, EYE_WIDTH]
                               58.5         [SLOTID, LANE, Loss, EYE_WIDTH]
                               62.4         [SLOTID, LANE, Loss, EYE_WIDTH]
                               66.3         [SLOTID, LANE, Loss, EYE_WIDTH]
                               70.2         [SLOTID, LANE, Loss, EYE_WIDTH]
              2     9.946152   50.7         [SLOTID, LANE, Loss, EYE_WIDTH]
                               54.6         [SLOTID, LANE, Loss, EYE_WIDTH]
                               58.5         [SLOTID, LANE, Loss, EYE_WIDTH]

现在，我的要求是在数据框中（最好在该Loss变量旁边）打印每个“丢失”值的出现次数。