Another option:
egen total = rowtotal(ndrug*) if ndrug1<. | ndrug2<. | ndrug3<.
Friedrich
On Wed, Apr 2, 2008 at 10:09 AM, Svend Juul <[email protected]> wrote:
> Ziad wrote:
>
> Any tips how to add (summation) 3 variables when one has empty value
> (example below)
> I did not want to use replace var=0 if var==. because i want to know
> when all the 3 variables (ndrug1,ndrug2 and ndrug3 have empty values
> at the same time)
>
> id visitn ndrug1 ndrug2 ndrug3 total
> ------------------------------------------------------------------------
> -----
> 1 2 . 2 1 3
> 1 4 2 . 3 5
> 1 8 2 3 3 8
> 1 12 . . . .
> 2 2 . . 2 2
> 2 4 1 1 . 2
>
> ===================================================================
>
>
> . egen nonmiss = rownonmiss(ndrug*)
> . egen total = rowtotal(ndrug*) if nonmiss>0
> . list, clean
>
> id visitn ndrug1 ndrug2 ndrug3 nonmiss total
> 1. 1 2 . 2 1 2 3
> 2. 1 4 2 . 3 2 5
> 3. 1 8 2 3 3 3 8
> 4. 1 12 . . . 0 .
> 5. 2 2 . . 2 1 2
> 6. 2 4 1 1 . 2 2
>
> Hope this helps
> Svend
> __________________________________________
>
> Svend Juul
> Institut for Folkesundhed, Afdeling for Epidemiologi
> (Institute of Public Health, Department of Epidemiology)
> Vennelyst Boulevard 6
> DK-8000 Aarhus C, Denmark
> Phone: +45 8942 6090
> Home: +45 8693 7796
> Email: [email protected]
> __________________________________________
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