Preserve, Restore and Reshape

[Katja Lepper]

Hello,

I have a strange problem with a foreach loop with a reshape command which looks like this:

levelsof id_ne, local(levels)
foreach l of local levels {
preserve

drop if id_ne != `l'
keep raeume time_stamp_trunc persgradtagzahl

reshape wide persgradtagzahl, i(time_stamp_trunc) j(raeume)

save `path_temp'tempfile`l'.dta, replace

restore
}

The first round of the loop works perfectly fine. When ending the first loop, the data is restored. After that (only after the first round), the code seems to skip the drop and keep command which leads stata to not beeing able to conduct the reshape command.

Any ideas?

[Sergio Correia]

1. How do you know the drop+keep are skipped? Note that if reshape fails, since you run an earlier reshape the data you'll see is how it was when you ran preserve (i.e. before the two commands were executed)

2. You don't really need to preserve *every loop* if you use the "restore, preserve" option. Something like:

preserve
for .. {
keep + drop + save
restore, preserve
}