Hello Rick,

Thanks for the helpful blogs... I recently read the post regarding the creating matrix by using do loops and have a question for you. I am very new to proc IML and really want to tackle it with all of your guys advises..By folloing a logic, I am trying to create a matrix and pass my variables that had been read from the data set into the matrix.
this is what I do
proc IML;
USE work.Test1;
READ ALL VAR {Var 1....Var 26} into rm ;
CLOSE work.Test1;
n=NROW(rm);
d=J(n,1,0);
c=d;
c=n[,2:27]-n[,1:26];
x=n|d||c;
free n;
quit;
This is what passed through the log:
ERROR: (execution) Matrix has not been set to a value.
operation : || at line 1006 column 9
operands : d, c

d 0 row 0 col (type ?, size 0)

How can I deal with the problem? I would highly appreciate the specific advise