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Kushan said
I have a column name permno in my dataset. It is a numerical column,
and I want to loop over it. This is what I did:
foreach num in permno {
// do something
}
Martin explained why it didn't work, and suggested using -levelsof-.
But under the assumption these are company permnos from CRSP, for
instance, each observation has a unique value; they're just not
consecutive integers.
If you want to do something to every observation, realize that Stata
is not SAS. Any expression you give in a -generate- (or -replace-)
statement will automatically apply to each observation. If you have a
variable totassets, for instance,
gen lta = log (totassets)
will create the value log total assets for every observation. There is
no need to loop over observations, and in many cases, it is a bad idea
to do so. The principle is that commands operate on the whole current
dataset unless modified by -in range- or -if exp-.
Kit Baum | Boston College Economics & DIW Berlin | http://ideas.repec.org/e/pba1.html
An Introduction to Stata Programming
| http://www.stata-press.com/books/isp.html
An Introduction to Modern Econometrics Using Stata | http://www.stata-press.com/books/imeus.html
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