How to merge column in output table from proc transpose?

[mikepark]

proc transpose data=TableA out=TableB prefix=name_;

by &key.;

var name;

run;

The output table from the proc transpose has 3 columns that I need to merge. 

The columns are name_1, name_2, and name_3.

How do I combine these columns together?

I tried this below and it did not work. I keep getting an error that the variables that were created during the proc transpose are not initialized. I see them in the data set so I don't understand why I can't use them. 

data TableB(keep=patient_id drug_id drug_combo); 
set TableA;
drug_combo = cats(' ', trim(name_1), trim(name_2), trim(name_3));
run;

[Astounding · Accepted solution]

Those variables are part of TableB, not TableA.  You would need to begin with something like:

data tableC;

set TableB;

[mikepark]

Of course. I must have been sleepy.