⨳ Setting %array Values Through %do_over ⨳

2014 May 03, Saturday

I’ve been using Ted Clay’s %array and %do_over macros lately. a lot. Everytime I think I’ve hit a wall with what these two macros can do, I look back at Ted’s Coders’ Corner paper for SUGI 31–that’d be SGF 2006 in SAS Global Forum terms.

Recently, I was working on a macro to handle a set of an unknown number of variables. Depending on the number of variables in each set, I had to kick off another macro and, conditionally, execute some other statements.

This sounded like the perfect situation for %array and %do_over.

So I checked if this works:

%array(seq, values=%do_over(values=1-5, phrase=V?));
%put %do_over(seq);

good news: it worked exactly as one would expect.

V1     V2     V3     V4     V5

this can taken a bit further by specifying the number of elements in a different array as the end point…

%array(abc, values=A B C);
%array(seq, values=%do_over(values=1-&ABCN, phrase=V?));
%put %do_over(seq abc, phrase=?seq is ?abc.);

which does this

V1 is A.     V2 is B.     V3 is C.

and even further by calling a macro.

%macro echo(x,y);
    %put &X. is &Y..;
%mend;
%do_over(seq abc, macro=echo);

which makes this

V1 is A.
V2 is B.
V3 is C.

retrofitting a keyword macro is simple enough.

%macro echoagain(x, y, z=&y);
    %put &X. is &Y. (Z=&Z.).;
%mend;
%do_over(seq abc, macro=echoagain);

returning these results

V1 is A (Z=A).
V2 is B (Z=B).
V3 is C (Z=C).