Python：按多个列排序，并添加一个带有顺序号的列

假设以下数据帧：

ID          Date1           Date2       Col1      Col2       DateDiff 
22000118    2019-11-06      2019-11-15  0.562231  0.470641   9 days
22000118    2019-11-06      2019-12-20  0.375000  0.319872   44 days
30          2019-11-06      2019-11-15  0.916047  0.730626   9 days
30          2019-11-06      2019-12-20  0.519936  0.423861   44 days
22000118    2020-11-05      2025-12-19  0.316772  0.301951   1870 days
30          2020-11-05      2026-12-18  0.256964  0.234729   2234 days
30          2020-11-05      2027-12-17  0.250835  0.230236   2598 days
22000118    2019-11-06      2020-01-17  0.330995  0.287567   72 days
22000118    2020-11-05      2026-12-18  0.310234  0.296930   2234 days
22000118    2020-11-05      2027-12-17  0.305502  0.293349   2598 days
30          2019-11-06      2020-01-17  0.443920  0.366206   72 days
30          2020-11-05      2025-12-19  0.264916  0.240628   1870 days

我想按列

ID、Date1

和

DateDiff

（其中

Date1

是

datetime64

类型，

DateDelta

是

timedelta64

类型）对其进行排序，并添加一个带有订单号的列，如下示例所示：

ID          Date1           Date2       Col1      Col2       DateDiff    Order
30          2019-11-06      2019-11-15  0.916047  0.730626   9 days      1
30          2019-11-06      2019-12-20  0.519936  0.423861   44 days     2
30          2019-11-06      2020-01-17  0.443920  0.366206   72 days     3
30          2020-11-05      2025-12-19  0.264916  0.240628   1870 days   1
30          2020-11-05      2026-12-18  0.256964  0.234729   2234 days   2
30          2020-11-05      2027-12-17  0.250835  0.230236   2598 days   3
22000118    2019-11-06      2019-11-15  0.562231  0.470641   9 days      1
22000118    2019-11-06      2019-12-20  0.375000  0.319872   44 days     2
22000118    2019-11-06      2020-01-17  0.330995  0.287567   72 days     3
22000118    2020-11-05      2025-12-19  0.316772  0.301951   1870 days   1
22000118    2020-11-05      2026-12-18  0.310234  0.296930   2234 days   2
22000118    2020-11-05      2027-12-17  0.305502  0.293349   2598 days   3

---

我已经知道如何使用

sort\u值对其进行排序，但我不知道如何添加带有订单号的最后一列。
在您按
sort\u值排序后

df['Order'] = df.groupby(['ID','Date1']).cumcount()+1