I have a database in SPSS structured like the following table:
| ID | Gender | Age | Var1 | Var... |
|---|---|---|---|---|
| 1 | 0 | 7 | 3 | ... |
| 2 | 1 | 8 | 4 | ... |
| 3 | 1 | 9 | 5 | ... |
| 4 | 1 | 9 | 2 | ... |
I want to select only the first n (e.g.: 150) cases, where Gender = 1 and Age = 9, so in the table above the 3. and 4. case. How can I do it? Thanks!
compute filter_ = $sysmis.
compute counter_ = 0.
if $casenum=1 and (Gender = 1 and Age = 9) counter_ =1 .
do if $casenum <> 1.
if ~(Gender = 1 and Age = 9) counter_ = lag(counter).
if (Gender = 1 and Age = 9) counter_ = lag(counter) +1.
end if.
compute filter_ = (Gender = 1 and Age = 9 and counter<= 150).
execute.
I am not sure if this is the most efficient way, but it gets the job done. We use the counter_ variable to assign an order number for each record which satisfies the condition ("counting" records with meet the criteria, from the top of the file downwards). Then create a filter of the first 150 such records.
The below will select the first 150 cases where gender=1 AND age=9 (assuming 150 cases meet that criteria).
N 150.
SELECT IF (Gender=1 AND Age=9).
EXE .
Flipping the order of N and SELECT IF () would yield the same result. You can read more about N in the IBM documentation