Thanks for all the hints, everyone. For now, I had to put the matrix into MATLAB to do the matrix operations; MATLAB is quite straight foward to code and I'm on an extremely tight deadline to provide some of the many answers in this project.   However, I still need to streamline it all into SAS, since all base matrices will be estimated from a dataset containing ~1.7 million rows and growing. The project will require calculating anywhere between 40-50 different matrices from the SAS dataset, then doing all the operations. I haven't had the time to figure out how to get proc iml to READ a matrix from a dataset. If anyone has the code for this and doesn't mind sharing it, I'd really appreciate the time saving tip, I'm on a tight schedule here. In case someone in the community is interested in Markov chains: the 10 by 10 matrices are basic Markov transition probability matrices, all estimated from the SAS dataset with a bunch of different criteria.  Item 5 in the answer is a misunderstanding: the final goal really are scalars, each one the expected future values of a certain index. Each scalar is the nth row of the matrix (1 by 10 vector of probabilities) multiplied by the 10 by 1 column vector of the 10 possible index values. I think picking the rows with a macro will be straightfoward to get once the matrix is read as matrix: use a vector with zeroes everywhere and a 1 in the position of the row I want to pick.      ... View more

Perfect homework! Thanks ... View more

Thanks, it works perfectly! ... View more

Thanks, Kurt. Your correction works perfectly! ... View more

same result with: %macro apaga; %do i=1 %to 9; %let EMPTY=1; data _null_; set x&i; call symput('EMPTY','0'); /* this will only occur if &DATA is not empty */ run; %end; /* Now, you just need to check the macro var for its value at the end, to perform (or not) a proc dataset delete,*/ %if &EMPTY %then %do; proc datasets lib=work nolist; delete work.x&i; %end;/*%end;***also tried put it all inside teh first 2 loops and the result was the same***/ quit; %mend; %apaga; run; ... View more

same result. If the variable x is binary, if x means the same as if x=1. ... View more

same results.. counts nobs but does not delete empties... ... View more

Can you please tell me where I missed something? I need to run a bunch of macros that keep creating 9 temporary datasets, then delete the empty one before going to the next step of the calculations.   I tried your macro after I created the temp files. It checks how many observations but does not delete the empty ones.   Thanks! %macro apaga; %let EMPTY=1; %do i=1 %to 9; data _null_; set x&i; call symput('EMPTY','0'); /* this will only occur if &DATA is not empty */ run; %end; /* Now, you just need to check the macro var for its value at the end, to perform (or not) a proc dataset delete, */ %if &EMPTY %then %do; proc dataset lib=work nolist; delete work.x&i; /* delete dataset */ quit; %end; %mend; %apaga; run; ... View more