st: RE: many zip codes to select (about 700)

["Jens M. Lauritsen" <JM.Lauritsen@dadlnet.dk>]

The obvious way to this in my view would be:
1. Have your actual dataset in one file, say Mydata.dta
2. Create a second dataset with the desired zip codes, say ZipCodes.dta  If 
you have those 700 in a txt file it is easy:

*read from the ascii-txt file with the 700 numbers:
insheet zip using mylist.txt
sort zip
save ZipCodes.dta

* read your actual dataset
use Mydata.dta
sort zip

* merge with the zipcodes dataset based on the zip
merge zip using ZipCodes.dta

/*now a new variable _merge is made which has three values:
1: Only in Mydata.dta
2: Only in ZipCodes
3: In both
*/
tab _merge

* then as a test find zipcodes you thought were there:
tab zip if _merge == 2

* And keep only the relevant ones.
Then find the
drop if _merge == 2

Kind Regards
Jens M.Lauritsen
Jens M. Lauritsen, Consultant,MD. PhD.
Accident Analysis Group, Odense University Hospital,
Odense, Denmark
e-mail: JM.Lauritsen@dadlnet.dk
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