Date:         Wed, 3 Jan 2001 07:54:41 -0500
Reply-To:     125241N@KNOTES.KODAK.COM
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         John Hixon <125241N@KNOTES.KODAK.COM>
Comments: To: Raphael.HALIMI@GEP.FR
Content-type: text/plain; charset=us-ascii

From: John Hixon


I am resending this last post since I accidentally sent it with
embedded RTF....(Lotus Notes still seems quirky to me and I've been
using it for years!).  I'm on digest for SAS-L but just rec'd the post and
noticed the RTF binary garbage and funny "extra characters" in my
last post.  Sorry about that.  In the future I will be sure NOT to
send anyting but plain text!

Cheers,

John Hixon
Eastman Kodak Co
Rochester, NY USA

Here is the code again:

%let m=7;   * choose "m" of "n";
%let n=12;   * Choose "m" of "n" ;

* this data step is just to put the Number of
* necessary combinations into a macro variable;
data _null_;
    combos=comb(&n,&m);  * get the numer of cominations;
    put combos=;
    call symput('N_Combos',put(combos,best8.0));  * put into a macro var;
run;

* Proc plan is useful for generating
"Choose m of n" combinations (or, also,
for choosing permutations);
proc plan;
    factors Dummy=&N_Combos    /*  This is the Number of Combinations*/
    FactorA=&m of &n comb ;    /* Choose m of n combos...see Proc Plan
doc*/
    output out=design          /* name the 12 Factor levels */
        FactorA cvals=('a123' 'b123' 'c123' 'd111' 'e111' 'f111'
                       'a456' 'b456' 'c456' 'd222' 'e222' 'f222');
run;
* Notice that the required "list" is shown above as 12 arbitrary strings;

* print the dataset;
proc print data=design;
run;

* Notice that we need to rearrange the data set, so output to temp text
file;
data _null_;
    file 'd:\temp\junk.txt';
    set design;
    put Dummy FactorA;
run;

* read back the temp text file and reformat;
data design2 (drop=i index Dummy);
    infile 'd:\temp\junk.txt';
    array A{&m} $ A1-A&m ('error1' 'error2' 'error3');
        do i=1 to &m*&N_Combos;
            index=mod(i,&m)+1;
            if index=1 then do;
                input Dummy$  A{index} @@;
                output;
            end;
            if index ne 1 then input Dummy$ A{index} @@;
        end;
run;

* desired output;
proc print data=design2;
run;


* To do permutations just make a slight modification as seen below:;

%let n=6;  *this will yield 6!=720 permutations;
data _null_;
    perms=perm(&n);  * get the numer of cominations;
    put perms=;
    call symput('N_Perms',put(perms,best12.0));  * put into a macro var;
run;

* Proc plan is useful for generating
"Choose m of n" combinations (or, also,
for choosing permutations);
proc plan;
    factors Dummy=&N_Perms    /*  This is the Number of Permutations*/
    FactorA=&n perm ;    /* Choose n! permutations...see Proc Plan doc*/
    output out=design          /* name the 6 Factor levels */
        FactorA cvals=('a123' 'b123' 'c123' 'd111' 'e111' 'f111');
run;
* Notice that the required "list" is shown above as 6 arbitrary strings;

* print the dataset;
proc print data=design;
run;

* Notice that we need to rearrange the data set, so output to temp text
file;
data _null_;
    file 'd:\temp\junk.txt';
    set design;
    put Dummy FactorA;
run;

* read back the temp text file and reformat;
data design2 (drop=i index Dummy);
    infile 'd:\temp\junk.txt';
    array A{&n} $ A1-A&n ;
        do i=1 to &N_Perms;
            index=mod(i,&n)+1;
            if index=1 then do;
                input Dummy$  A{index} @@;
                output;
            end;
            if index ne 1 then input Dummy$ A{index} @@;
        end;
run;

* desired output;
proc print data=design2;
run;