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Re: st: Adding variables containing empty values


From   "Friedrich Huebler" <fhuebler@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Adding variables containing empty values
Date   Wed, 2 Apr 2008 13:52:33 -0400

Another option:

egen total = rowtotal(ndrug*) if ndrug1<. | ndrug2<. | ndrug3<.

Friedrich

On Wed, Apr 2, 2008 at 10:09 AM, Svend Juul <SJ@soci.au.dk> 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:  sj@soci.au.dk
>  __________________________________________
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