SAS - Creating combinations of different independant variables with lags - sas

Question

I'd like to create dynamic entries in a data set (in SAS) formed using the names of variables (e.g. VarA, VarB, VarC) each having lags up to 4.
The input data set HAVE has this information (the column names are Variables and Values):
Variables Values
VarA 0
VarB 0
VarC 0
Lags 4
and the output data set WANT should be something like below (Var1, Var2, and Var3 are dynamic column names i.e. appending 1,2,3 to any string Var)
Var1 Var2 Var3
VarA VarB VarC
VarA1 VarB1 VarC1
..
VarA4 VarB4 VarC4
The intention is to have this work for any number of variables in HAVE data set.
Thanks

Answer 1

The following code returns what you want. Please modify according to your needs.
/*sample input dataset*/
data have;
input Variables $ Values;
datalines;
VarA 0
VarB 0
VarC 0
Lags 4
;
run;
/*get the no. of lags form the input dataset*/
proc sql noprint;
select Values into :num_of_lags from have where upcase(variables)='LAGS';
quit;
/*transpose the input dataset such that the VarA, VarB, VarC are put in columns Var1, Var2, & Var3 respectively*/
/*have_t, the transposed dataset only has 1 row.*/
proc transpose data = have out = have_t(drop = _name_) prefix = var;
where upcase(variables) ne 'LAGS';
var variables;
run;
/*replicate the 1 row in have_t num_of_lags times*/
data pre_want;
set have_t;
array myVars{*} _character_;
do j= 1 to &num_of_lags+1;
do i = 1 to dim(myVars);
myVars[i]=myVars[i];
end;
output;
end;
run;
/*final dataset*/
data want;
set pre_want;
array myVars{*} _character_;
if _N_>1 then do;
do i = 1 to dim(myVars);
myVars[i]=compress(myVars[i]!!_n_-1);
end;
end;
drop i j;
run;
proc print data = want; run;
Output:
var1 var2 var3
VarA VarB VarC
VarA1 VarB1 VarC1
VarA2 VarB2 VarC2
VarA3 VarB3 VarC3
VarA4 VarB4 VarC4