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Writing frequently-used code as macros

Several operations are so standard that if you write them up as macros and save them in a macro file, you will be spared a lot of typing. You can then automatically include this macro file in all your SAS programs - see the section on autoexec.sas, Section 15.9.

An example is the merge algorithm. Merging always proceeds in the same way. You are given two datasets and the by-variables, you sort them by the by-variables and then merge them. I wrote up a ``standard merge'' macro named %stdmerge:

%macro stdmerge(inds1, inds2, byvar, outds);
    proc sort data=&inds1 nothreads;
       by &byvar;
    run;

    proc sort data=&inds2 nothreads;
       by &byvar;
    run;    
    data &outds;
       merge &inds1(in=a) &inds2(in=b);
       by &byvar;
       if a and b;
    run;
%mend;
   

In the SAS programs I write, when I want to merge two datasets, all I need to do is say

    %stdmerge(firstdataset, seconddataset, by-variable-list, outputdataset)
   

instead of laboriously typing out the whole thing every time. This clears up an enormous amount of clutter from my SAS programs, making them much more readable.