sas macro resolving issue - variables

Question

Dummy data:
MEMNAME _var1 var2 var3 var4
XY XYSTART_1 XYSTATT_2 XYSTAET_3 XYSTAWT_4
I want to create a macro variable that will have data as TEST_XYSTART, TEST_XYSTATT, TEST_XYSTAET, TEST_TAWT.... how can I do this in datastep without using call symput because I want to use this macro variable in the same datastep (call symput will not create macro variable until I end the datastep).
I tried as below (not working), please tell me what is the correct way of write the step.
case = "TEST_"|| strip(reverse(substr(strip(reverse(testcase(i))),3)));
%let var = case; (with/without quotes not getting the desired result).
abc= strip(reverse(substr(strip(reverse(testcase(i))),3)));
%let test = TEST_;
%let var = &test.abc;
I am getting correct data with this statement: strip(reverse(substr(strip(reverse(testcase(i))),3)))
just not able to concatenate this value with TEST_ and assign it to the macro variable in a datastep.
Appreciate your help!

Answer 1

It makes no sense to locate a %LET statement in the middle of a data step. The macro processor evaluates the macro statements first and then passes the resulting code onto SAS to evaluate. So if you had this code:
data want;
set have;
%let var=abc ;
run;
It is the same as if you placed the %LET statements before the DATA statement.
%let var=abc ;
data want;
set have;
run;
If you want to reference a variable dynamically in a data step then use either an index into an array.
data want;
set have;
array test test_1 - test_3;
new_var = test[ testnum ] ;
run;
Or use the VvalueX() function which will return the value of a variable whose name is a character expression.
data want;
set have;
new_var = vvaluex( cats('test_',testnum) );
run;