<>
To be fair, we should mention the -cw- option which, in your case, would
omit the groups 3 and 4 completely.
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Michael
Mitchell
Gesendet: Mittwoch, 10. Februar 2010 03:51
An: [email protected]
Betreff: st: Collapse with sum function and missing values
Greetings
I am befuddled by the following example that uses the -collapse-
command with the -(sum)- function...
. clear
. input group x
group x
1. 1 10
2. 1 11
3. 1 12
4. 2 20
5. 2 21
6. 2 22
7. 3 .
8. 4 .
9. 4 .
10. end
.
. collapse (sum) x , by(group)
. list
+------------+
| group x |
|------------|
1. | 1 33 |
2. | 2 63 |
3. | 3 0 |
4. | 4 0 |
+------------+
Shouldn't the value of -x- for groups 3 and 4 be missing, not zero.
To me, the sum of a series of missing values is a missing value. I am
doing a collapse for about 100 variables (100 x values) and need the
value to be defined as missing (not 0) in such cases. Any ideas?
Thanks,
Michael
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
