我想生成Price2变量，它是每秒price值的总和，并将此新值添加到每个时间值相同的最后一行。
以下是我的数据示例（Price2变量除外）。结果是price2 var。如下所示。 Day和Time变量是字符串。
+------+-----------+----------+-------+-------------+
| Name | Day | Time | Price | Price2 |
+------+-----------+----------+-------+-------------+
| A | 24-Mar-08 | 10:30:01 | 1 | .|
| A | 24-Mar-08 | 10:30:01 | 4 | .|
| A | 24-Mar-08 | 10:30:01 | 3 | 8|
| A | 24-Mar-08 | 11:03:12 | 1 | .|
| A | 24-Mar-08 | 11:03:12 | 4 | 5|
| A | 25-Mar-08 | 10:30:01 | 3 | .|
| A | 25-Mar-08 | 10:30:01 | 8 | 11|
| A | 25-Mar-08 | 11:13:59 | 3 | .|
| A | 25-Mar-08 | 11:13:59 | 2 | .|
| A | 25-Mar-08 | 11:13:59 | 5 | .|
| A | 25-Mar-08 | 11:13:59 | 3 | 13|
| A | 25-Mar-08 | 11:59:01 | 1 | 1|
| B | 24-Mar-08 | 10:30:01 | 3 | .|
| B | 24-Mar-08 | 10:30:01 | 4 | 7|
| B | 24-Mar-08 | 11:30:01 | 3 | .|
| B | 24-Mar-08 | 11:30:01 | 5 | 8|
| B | 25-Mar-08 | 11:30:01 | 7 | .|
| B | 25-Mar-08 | 11:30:01 | 4 | .|
| B | 25-Mar-08 | 11:30:01 | 2 | 13|
| B | 25-Mar-08 | 12:00:00 | 6 | 6|
+------+-----------+----------+-------+-------------+
如何使用Stata计算Price2变量？
答案 0 :(得分：2)
请注意，数据作为代码，如下所示，以及我对您之前的帖子的回答，对于人们来说更容易使用。这与您上面的示例相似。
clear
input str1 Name str9(Day Time) float(Price Size)
"A" "24-Mar-08" "10:30:01" 1 3
"A" "24-Mar-08" "10:30:01" 4 4
"A" "24-Mar-08" "10:30:01" 3 2
"A" "24-Mar-08" "11:03:12" 1 4
"A" "24-Mar-08" "11:03:12" 4 1
"A" "25-Mar-08" "10:30:01" 3 4
"A" "25-Mar-08" "10:30:01" 8 2
"A" "25-Mar-08" "11:13:59" 3 2
"A" "25-Mar-08" "11:13:59" 2 4
"A" "25-Mar-08" "11:13:59" 5 5
"A" "25-Mar-08" "11:13:59" 3 3
"A" "25-Mar-08" "11:59:01" 1 5
"B" "24-Mar-08" "10:30:01" 3 6
"B" "24-Mar-08" "10:30:01" 4 1
"B" "24-Mar-08" "11:30:01" 3 2
"B" "24-Mar-08" "11:30:01" 5 1
"B" "25-Mar-08" "11:30:01" 7 3
"B" "25-Mar-08" "11:30:01" 4 6
"B" "25-Mar-08" "11:30:01" 2 2
"B" "25-Mar-08" "12:00:00" 6 2
end
bysort Name Day Time: egen wanted = total(Price)
by Name Day Time: replace wanted = . if _n < _N
list, sepby(Name Day Time)
+-----------------------------------------------------+
| Name Day Time Price Size wanted |
|-----------------------------------------------------|
1. | A 24-Mar-08 10:30:01 1 3 . |
2. | A 24-Mar-08 10:30:01 4 4 . |
3. | A 24-Mar-08 10:30:01 3 2 8 |
|-----------------------------------------------------|
4. | A 24-Mar-08 11:03:12 1 4 . |
5. | A 24-Mar-08 11:03:12 4 1 5 |
|-----------------------------------------------------|
6. | A 25-Mar-08 10:30:01 3 4 . |
7. | A 25-Mar-08 10:30:01 8 2 11 |
|-----------------------------------------------------|
8. | A 25-Mar-08 11:13:59 3 2 . |
9. | A 25-Mar-08 11:13:59 2 4 . |
10. | A 25-Mar-08 11:13:59 5 5 . |
11. | A 25-Mar-08 11:13:59 3 3 13 |
|-----------------------------------------------------|
12. | A 25-Mar-08 11:59:01 1 5 1 |
|-----------------------------------------------------|
13. | B 24-Mar-08 10:30:01 3 6 . |
14. | B 24-Mar-08 10:30:01 4 1 7 |
|-----------------------------------------------------|
15. | B 24-Mar-08 11:30:01 3 2 . |
16. | B 24-Mar-08 11:30:01 5 1 8 |
|-----------------------------------------------------|
17. | B 25-Mar-08 11:30:01 7 3 . |
18. | B 25-Mar-08 11:30:01 4 6 . |
19. | B 25-Mar-08 11:30:01 2 2 13 |
|-----------------------------------------------------|
20. | B 25-Mar-08 12:00:00 6 2 6 |
+-----------------------------------------------------+