Array with Do Until?

[gpv2000]

I need to create 3 variables(var1 var2 var3) based upon the occurrence of conditions within the subject. I have the input dataset example and output dataset example below. I think and array with do until might work but I am not sure how to implement. Any suggestions?

Input Dataset: 

subject    None      Discomfort       Bad_Vision      Other
12345       1
12345                        1
12345                        1                         1
12345                        1                                             1
12345                        1                         1                  1
12345                                                                       1

Output Dataset:

Subject              Var1                 Var2               Var3
12345              NONE
12345              Discomfort
12345              Discomfort     Bad_vision
12345              Discomfort     Other
12345              Discomfort     Bad vision         Other 
12345              Other

[ballardw · Accepted solution]

Best is to provide example data in the form of a data step. Then there are no questions about variable type, name or characteristics. Also code can be tested against the supplied data.

Also best is to post code in a code box opened using the forum {I} icon to preserve formatting.

data have;
  input subject    None      Discomfort       Bad_Vision      Other;
datalines;
12345 1  .   .  .
12345 .  1   .  .
12345 .  1   1  .
12345 .  1   .  1
12345 .  1   1  1
12345 .  .   .  1
run;

data want;
   set have;
   array a None Discomfort Bad_vision Other;
   array var{3} $ 10;
   count=0;
   do i=1 to dim(a);
      if a[i] = 1 then do;
         count=count+1;
         var[count]=vname(a[i]);
      end;
   end;
   keep subject var: ;
run;
      

The above works for your example. If you ever have cases where NONE is one and the other variables are populated as well then the solution may require having a fourth variable.

the function VNAME gets the name of a variable referenced as an array element.

The VAR:  with the colon is a short cut list that refers to all variables whose names start with VAR;

[gpv2000]

Thank you. I will keep in mind the points you mentioned about data. Thanks again.