@John1231
As @Reeza already wrote: You should know your data and define the variable attributes upfront. Analyzing and changing the data every single time sounds like a bad idea.
If your problem is that you're creating monthly data with different variable lengths then combining the data using a PROC SQL UNION will pre-analyse your variable definitions and will take the longest length (=no truncation risk).
proc sql;
create table all_months as
select *
from dataset_201701
outer union corr
select *
from dataset_201702
;
quit;
... View more