topic permutations in SAS Programming

permutations

sasuser1000 — Thu, 15 Dec 2011 18:49:26 GMT

I need to create a code that will give me the below , but in a generic way

here i have 3, 2 and 1 open slots that can be filled only with A or B. but this can change in the future to 4 slots and a,b,c,d,e as a filling options. so the code need to be generic.

Any memory efficient idea on how to tackle this?

a a b

a b a

b a a

b b a

b a b

a b b

a b

b a

permutations

art297 — Thu, 15 Dec 2011 18:57:16 GMT

take a look at: http://support.sas.com/techsup/technote/ts498.html

permutations

sasuser1000 — Thu, 15 Dec 2011 19:00:30 GMT

Thanks, I saw it before but this is without returns, so chip can't appear twice..

permutations of 4 items taken 2 at a time

OBS R1 R2

1 Chip Pete

2 Chip Mike

3 Chip William

4 Pete Chip

5 Pete Mike

6 Pete William

7 Mike Chip

8 Mike Pete

9 Mike William

10 William Chip

11 William Pete

12 William Mike

permutations

art297 — Thu, 15 Dec 2011 19:22:55 GMT

Why not? You would just have to roll the permutations macro into a driver macro that accomplishes each level. I'm not sure how you want the final file, but that could easily be accomplished with proc append.

Try, e.g.,

%macro permute(r) / parmbuff; /* the parmbuff option assigns */

%let i=2; /* the invocation parameter list to the */

%let things=; /* macro variable &syspbuff */

%do %while (%Qscan(&syspbuff,&i,%STR(,%))) ne ); /* scan the syspbuff */

%let p&i="%Qscan(&syspbuff,&i,%STR(,%)))"; /* 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&r;

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;

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;

%mend permute;

%macro allperms(k);

%do L=1 %to &k.;

%permute(&L.,a,b,c)

%end;

%mend allperms;

%allperms(3)

permutations

sasuser1000 — Thu, 15 Dec 2011 19:37:13 GMT

Thanks but what i reaaly need is returns

the code give this

r1	r2	r3
a	b	c
a	c	b
b	a	c
b	c	a
c	a	b
c	b	a

but what i do not understand is how to do this on top of the above

a a a

a a b

a b b

a c c...etc

permutations

Ksharp — Fri, 16 Dec 2011 08:48:16 GMT

I don't understand why not like be:

aaa

bbb

a a b

a b a

b a a

b b a

b a b

a b b

a b

b a

%let num_slot=3;
%let list=a,b;




%let l=%sysfunc(tranwrd("&list",%str(,),%str(",")));
options nomprint nomlogic nosymbolgen;
%macro gen;
data _null_;
%do num=&num_slot %to 2 %by -1;
%do i=1 %to #
 do i&i=&l;
%end;
 if count(catx(' ',of i1 - i&num),i1) ne &num then put i1 - i#
%do j=1 %to #
 end;
%end;
%end;
do x=&l;put x;end;
stop;
run;
%mend gen;

%gen

Ksharp

permutations

art297 — Fri, 16 Dec 2011 13:06:47 GMT

If the following does what you want, then it would be easy to expand it to automatically account for the duplicates:

%permute(1,a,b,c)

%permute(2,a,a,b,b,c,c)

%permute(3,a,a,a,b,b,b,c,c,c)

permutations

sasuser1000 — Fri, 16 Dec 2011 15:50:56 GMT

Thanks Ksharp but I get this error when running the code, I think it's related to this "#" I am not sure I fully understand how the code works, so I don't know to which number should I input there

permutations

Ksharp — Fri, 16 Dec 2011 15:58:38 GMT

Why my code be changed? Is there some html sensitive word in my code?

%let num_slot=3;
%let list=a,b;




%let l=%sysfunc(tranwrd("&list",%str(,),%str(",")));
options nomprint nomlogic nosymbolgen;
%macro gen;
data _null_;
%do num=&num_slot %to 2 %by -1;
%do i=1 %to &num ;
 do i&i=&l;
%end;
 if count(catx(' ',of i1 - i&num),i1) ne &num then put i1 - i&num ;
%do j=1 %to &num ;
 end;
%end;
%end;
do x=&l;put x;end;
stop;
run;
%mend gen;

%gen

Ksharp

permutations

sasuser1000 — Fri, 16 Dec 2011 16:03:21 GMT

Thanks so much!

permutations

art297 — Fri, 16 Dec 2011 16:07:35 GMT

KSharp,

While the OP appears to be satisfied with the code, I don't think it does exactly what the OP had asked for. It appears to leave off the two and three-way same combinations like:

aaa

bbb

ccc

permutations

sasuser1000 — Fri, 16 Dec 2011 16:11:08 GMT

you are right, I didn't catch it.

permutations

Ksharp — Fri, 16 Dec 2011 16:12:31 GMT

Art.

Yes. That was what I am confused.

Actually I do not exactly know what OP want.

It is midnight at my time zone.

Good Night! Doctor Art.

Ksharp

permutations

art297 — Fri, 16 Dec 2011 16:16:10 GMT

Have a good night's rest KSharp. I was surprised to see you here this late.

permutations

sasuser1000 — Fri, 16 Dec 2011 16:22:52 GMT

ksharp, Art thank you both

I will use proc plan