On Wed, 11 Jun 1997 09:14:03 -0400, Jeanne M. Spicer wrote:

>I would like to be able to send a program "n" values and have it >generate all unique combinations of "r" values. So if I have 4 values >A,B,C,D I would like the program to generate all combinations of say 3 >values... >

I cribbed the following macro code from the SAS www server. It seems to work pretty well. Have fun!

Best, Alan

%macro permute(r) / parmbuff; /* the parmbuff option assigns */ %let i=2; /* the invocation parameter list to the */ %let things=; /* macro variable &syspbuff */ %do %while (%scan(&syspbuff,&i) ne ); /* scan the syspbuff */ %let p&i="%scan(&syspbuff,&i)"; /* to determine r */ %if &i=2 %then %let things=&&p&i; /* and count the number */ %else %let things=&things,&&p&i; /* of elements, n */ %let i=%eval(&i+1); %end; %let n=%eval(&i-2); data permute; drop i j copy; array check (*) $ 10 r1-r&r; /* create a total of r */ %do m=1 %to &r; /* variables for looping */ do r&m = &things; %end; copy=0; do i=2 to &r; /* look for duplicate items */ do j=1 to i-1; /* and keep the unique ones */ if check(j)=check(i) then copy+1; end; end; if copy = 0 then output; /* writes to a SAS data set */ if copy = 0 then put r1-r&r; /* writes to the log */ %do m=1 %to &r; end; /* end the r DO LOOPS */ %end; run; proc print uniform data=permute; title "permutations of &n items taken &r at a time "; run; %mend permute;

%macro combo(r)/parmbuff; %let i=2; %let things=; %do %while (%scan(&syspbuff,&i) ne ); %let p&i="%scan(&syspbuff,&i)"; %if &i=2 %then %let things=&&p&i; %else %let things=&things,&&p&i; %let i=%eval(&i+1); %end; %let n=%eval(&i-2); data combo; keep v1-v&r; array word $8 w1-w&n (&things); array rr (*) r1-r&r; array v $8 v1-v&r; %do i=1 %to &r; /* create the DO LOOPs */ %if &i=1 %then %do; do r&i=1 to &n-(&r-&i); %end; %else %do; do r&i=r%eval(&i-1)+1 to &n-(&r-&i); %end; %end; do k=1 to &r; /* select subscripted items */ v(k)=word (rr(k)); /* for a SAS data set */ put v(k) ' ' @; /* for log */ end; put; /* writes to log */ output; /* writes to a SAS data set */ %do i=1 %to &r; end; /* create ENDs for the DO LOOPs */ %end; put; run; proc print uniform data=combo; title "combinations of &n items taken &r at a time "; run; %mend combo;

%permute(2,Chip,Pete,Mike,William); %combo(4,Chip,Mike,Nan,Greg,Bob,Owen);

%combo(1,1,2,3,4,5); %combo(2,1,2,3,4,5); %combo(3,1,2,3,4,5); %combo(4,1,2,3,4,5); %combo(5,1,2,3,4,5);