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Creating combinations of items in the list

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Contributor
Posts: 26
Accepted Solution

Creating combinations of items in the list

Hello,

I have a list of variables:

data tab;

input var $;

datalines;

A

B

C

;

I need to create unique combinations of these variables:

A
AB
ABC
AC
B
BC
C

Thank you in advance for your help.



Accepted Solutions
Solution
‎08-28-2015 08:37 AM
Super User
Posts: 10,046

Re: Creating combinations of items in the list

The simplest way is using proc means . Otherwise if you consider about efficient, then using GRAYCODE().

Code: Program

data tab;
input var $;
datalines;
A
B
C
;
run;
proc transpose data=tab out=temp(drop=_name_);
var var;
run;
proc summary data=temp;
class col:;
output out=want(where=(_type_ ne 0));
run;

Xia Keshan

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Super User
Super User
Posts: 7,996

Re: Creating combinations of items in the list

Hi,

Something like:

data tab;

  input var $;

datalines;

A

B

C

;

run;

proc transpose data=tab out=ttab;

  var var;

run;

data want (keep=var1-var3);

  set ttab;

  length var1 var2 var3 $1;

  array col{3};

  array var{3};

  do i=1 to 3;

    var1=col{i};

    output;

    do j=i+1 to 3;

      var{j}=col{j};

      output;

    end;

    var1=""; var2=""; var3="";

  end;

run;

Contributor
Posts: 26

Re: Creating combinations of items in the list

Hi,

thank you for quick response.

I used your code but one combination is missing (A C)

Super User
Super User
Posts: 7,996

Re: Creating combinations of items in the list

Got a meeting now, will try to look later.  I had got to this, needs sorting of the characters and then nodupkey sort:

data tab;

  infile datalines missover;

  input var $;

datalines;

A

B

C

;

run;

proc sql;

  create table WANT as

  select  A.VAR as VAR1,

          B.VAR as VAR2,

          C.VAR as VAR3

  from    TAB A

  full join TAB B

  on      A.VAR ne B.VAR

  full join TAB C

  on      A.VAR ne C.VAR

  and     B.VAR ne C.VAR

  union all

  select  VAR as VAR1,

          "" as VAR2,

          "" as VAR3

  from    TAB ;

quit;

Solution
‎08-28-2015 08:37 AM
Super User
Posts: 10,046

Re: Creating combinations of items in the list

The simplest way is using proc means . Otherwise if you consider about efficient, then using GRAYCODE().

Code: Program

data tab;
input var $;
datalines;
A
B
C
;
run;
proc transpose data=tab out=temp(drop=_name_);
var var;
run;
proc summary data=temp;
class col:;
output out=want(where=(_type_ ne 0));
run;

Xia Keshan

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