way to calculate the porcentage n(x,x) in transpose table

[michtka]

Hi to everybody,

I try to understand the final code of table 3 to understand the porcentage,

the code use a condition  n(_1,t1)=.2 then.... , please check below the right expression,

but I would like to understand this " if condition n(_1,t1)=2 ", why 2?...and how can I found it in the SAS biobiography.

Thanks in advance. V

Here you are the code below, please run the code, and I want to understand  the if condition n in (data total3), the way to calculate the porcentagey to calculate the:

data new;

input subjid trt fday  tday;

    datalines;

    1  1 1 5

    2  1 . 4

    2  1 . 3

    3  1 1 -4

    3  2 1 5

    4  2 1 2

    4  1 1 5

    ;

    run;

     proc sql;

   create table total as

   select count(distinct subjid) as n, trt 'Treatment', 'number of subjects A' as col0

   from new

   where fday ne .

   group by trt;

   quit;

   proc transpose data=total out=totalt;

   by col0;

   id trt;

   var n;

   run;

    proc sql;

   create table total2 as

   select count(distinct subjid) as n, trt 'Treatment', 'number of subjects B' as col0

   from new

   where fday ne . and tday le  0

   group by trt;

   quit;

   proc transpose data=total2 out=total2t;

   by col0;

   id trt;

   var n;

   run;

data total3;

length trt1 trt2 $12;

merge totalt (rename=(_1=t1 _2=t2)) total2t;

if n(_1,t1)=2 then trt1=put(_1,3.)||'

('||put((100*(_1/t1)),5.2)||'%)';

else trt1='  0';

if n(_2,t2)=2 then trt2=put(_2,3.)||'

('||put((100*(_2/t2)),5.2)||'%)';

else trt2='  0';

run;

[Tom · Accepted solution]

The N() function counts the number of non missing arguments. So N(_1,t1) is testing that both the _1 and T1 variables are not missing.

It appears to be using this to decide whether to generate count and percentage or just to display a zero.

[michtka]

Thank you very much Tom.