Variable Combination and Flag Selection

[apolitical]

I have a list of variable names, and want to get all possible combinations of any number of variables from that list. Separately, each variable has a flag value of 0 or 1, for each combination, I also want to single out the variables with flag of 1 and put them together in a separate field. Also, I want a field with the number of variables selected, as well as a field with the number of flagged variables.

Example:

I start with this list

Name	Flag
V1	1
V2	0
V3	1

I want to get to this list:

Combo	Flagged_Vars	Num_Var	Num_Flag_Var
V1	V1	1	1
V2		1	0
V3	V3	1	1
V1 V2	V1	2	1
V1 V3	V1 V3	2	2
V2 V3	V3	2	1
V1 V2 V3	V1 V3	3	3

Thank you!

[Ron_MacroMaven]

see my response to 

Analyzing-Multiple-Response-Variables

Ron Fehd  macro maven

[apolitical]

I wrote this myself and I think it gives what I want. Thanks all.

data varlist;
length name $32.;
input name class_flag;
cards4;
var1 0
var2 1
var3 1
var4 0
;;;;
run;

%macro exhaust();

	data varlist;
	set varlist;
	id+1;
	if class_flag=1 then class_name=name;
	run;
	data combo_all;set _null_;run;

	proc sql;select count(*) into: varct from varlist;quit;
	%put &varct.;

	%do i=1 %to &varct.;

		%if &i.=1 %then %do;
			data combo;
			set varlist (rename=(name=Var_Combo class_flag=num_flag));
			num_var=1;
			if num_flag=1 then Class_Var=class_name;
			drop flag_name;
			run;
		%end;

		%if &i.>1 %then %do;
			proc sql;
			create table combo as 
			select 
			strip(a.Var_Combo)||"   "||strip(b.name) as Var_Combo,
			strip(a.Class_Var)||"   "||strip(b.class_name) as Class_Var,
			&i. as Num_Var,
			a.num_flag+b.class_flag as Num_Flag,
			max(a.id,b.id) as id
			from combo as a, varlist as b 
			where a.id < b.id 
			;
			quit;
		%end;

		data combo_all;
		set combo_all combo;
		run;

	%end;

%mend exhaust;


%exhaust();

[Ksharp · Accepted solution]

data have;
input Name	$ Flag;
cards;
V1 1
V2 0
V3 1
;

%let dsid=%sysfunc(open(have));
%let nobs=%sysfunc(attrn(&dsid,nlobs));
%let dsid=%sysfunc(close(&dsid));

data want;
set have end=last;
length combo  Flagged_Vars $ 200;
array x{&nobs};
array n{&nobs} $ 32 _temporary_;
array f{&nobs} _temporary_;
n{_n_}=name;
f{_n_]=flag;
if last then do; 
k=-1;
do i=1 to 2**&nobs;
 rc=graycode(k, of x{*});
 call missing(combo,Flagged_Vars);
 Num_Flag_Var=0;
 do j=1 to &nobs; 
  if x{j}=1 then do;combo=catx(' ',combo,n{j});	Num_Flag_Var+f{j}; end;
  if x{j}=1 and f{j}=1 then Flagged_Vars=catx(' ',Flagged_Vars,n{j});
 end;
 Num_Var=countw(combo);
 if Num_Var ne 0 then output;
end;
end;
keep combo 	Flagged_Vars Num_Var	Num_Flag_Var;
run;

[apolitical]

Tried it and it works. Thank you!