Hi, I assume you want to solve a linear or (mixed-)integer programming problem. PROC LP is a legacy proc, the current procs for this purpose are OPTMODEL, OPTLP and OPTMILP. Specifically for what you describe, OPTMODEL is probably the best choice. Here a link to the documentation (SAS/OR 12.1, but OPTMODEL is available since quite a few versions): http://support.sas.com/documentation/cdl/en/ormpug/63975/HTML/default/viewer.htm#optmodel_toc.htm I don't quite understand the details of you question, but with a basic understanding of modeling optimization problems you should be able to state the model for your optimization problem independently from the data files and OPTMODEL also supports loops. I hope this helps Philipp ... View more