topic Re: Generate Unique Combinations of a Series in SAS Procedures

Generate Unique Combinations of a Series

SAShole — Thu, 02 Aug 2012 21:17:12 GMT

I want to generate all possible unique combinations for a series. For Example,

data have;

input combinations $1.;

cards;

;

run;

I want a column that has ( i think this works out to 32 distinct combinations, 2^5, no?)

ABC

ABCDE

......

Thank you,

Re: Generate Unique Combinations of a Series

art297 — Thu, 02 Aug 2012 21:56:17 GMT

I think 2^5 -1

data _null_;

array a[5] $ ('A' 'B' 'C' 'D' 'E');

n = dim(a);

do k=1 to n;

do j=1 to comb(n,k);

counter+1;

call allcomb(j,k,of a

);

put counter 5. +3 @;

do i = 1 to k;

put a $5. @;

end;

put;

end;

run;

Re: Generate Unique Combinations of a Series

SAShole — Thu, 02 Aug 2012 22:55:40 GMT

Thanks Art!

Can you show me how to modify this code such that I can have a column with all the combinations?

Re: Generate Unique Combinations of a Series

Haikuo — Thu, 02 Aug 2012 23:08:25 GMT

Question: for example, will 'AB' be equivalent to 'BA'? in other words, will the order matter?

Haikuo

Re: Generate Unique Combinations of a Series

SAShole — Thu, 02 Aug 2012 23:14:36 GMT

For this i'm treating AB as equivalent to BA. Order does not matter.

Re: Generate Unique Combinations of a Series

PGStats — Thu, 02 Aug 2012 23:54:38 GMT

So, what you want is all possible subsets :

data test(keep=k sub);

array II{5} (5*0);

length sub $5;

k = -1;

do i = 1 to 2**5;

call graycode (k, of II{*});

call missing(sub);

do j = 1 to 5;

if II{j} then sub = cats(sub,char("ABCDE",j));

end;

output;

end;

run;

Re: Generate Unique Combinations of a Series

art297 — Thu, 02 Aug 2012 23:59:51 GMT

Jeffrey,

Not sure what you are asking regarding one column. Possibly something like:

data want(keep=want);

array a[5] $ ('A' 'B' 'C' 'D' 'E');

length temp $5 want $500;

format want $500.;

n = dim(a);

want='';

do k=1 to n;

do j=1 to comb(n,k);

counter+1;

call allcomb(j,k,of a

);

temp='';

do i = 1 to k;

temp=catt(temp, a);

end;

want=catx(',',want,temp);

end;

run;

Re: Generate Unique Combinations of a Series

Ksharp — Fri, 03 Aug 2012 03:30:31 GMT

I found an interesting way. Maybe you like it.

data have;
  input combinations $1.;
  cards;
A
B
C
D
E
;
run;
proc transpose data=have out=x(keep=col:);
var combinations;
run;
proc means data=x noprint;
class _all_;
output out=want(keep=col:);
run;
data want;
 set want;
 combination=cats(of col:);
run;

Ksharp