SAS - hash tables and has_next

Question

I'm looking for an elegant solution to the below issue that will help avoid code duplication. You can see that this line:

put auction_id= potential_buyer= ;* THIS GETS REPEATED;

Gets repeated in this code:

data results;

  attrib potential_buyer length=$1;

  set auction;

  if _n_ eq 1 then do;
    declare hash ht1(dataset:'buyers', multidata: 'y');
    ht1.definekey('auction_id');
    ht1.definedata('potential_buyer');
    ht1.definedone();
    call missing (potential_buyer);
  end;


  **
  ** LOOP THROUGH EACH POTENTIAL BUYER AND PROCESS THEM
  *;
  if ht1.find() eq 0 then do;

    put auction_id= potential_buyer= ;* THIS GETS REPEATED;

    ht1.has_next(result: ht1_has_more);
    do while(ht1_has_more);
      rc = ht1.find_next();

      put auction_id= potential_buyer= ;* THIS GETS REPEATED;

      ht1.has_next(result: ht1_has_more);
    end;
  end;
run;

I've simplified the above example to a single line as the real code block is quite long and complex. I'd like to avoid using a %macro snippet or a %include if possible as I'd like to keep the logic "within" the data step.

Here's some sample data:

    data auction;
      input auction_id;
    datalines;
    111
    222
    333
    ;
    run;

    data buyers;
      input auction_id potential_buyer $;
    datalines;
    111 a
    111 c
    222 a
    222 b
    222 c
    333 d
    ;
    run;

Answer 1

I figured it out. Turned out to be pretty simple in the end just had a little trouble wrapping my brain around it:

data results;

  attrib potential_buyer length=$1;

  set auction;

  if _n_ eq 1 then do;
    declare hash ht1(dataset:'buyers', multidata: 'y');
    ht1.definekey('auction_id');
    ht1.definedata('potential_buyer');
    ht1.definedone();
    call missing (potential_buyer);
  end;


  **
  ** LOOP THROUGH EACH POTENTIAL BUYER AND PROCESS THEM
  *;
  if ht1.find() eq 0 then do;

    keep_processing = 1;
    do while(keep_processing);

      put auction_id= potential_buyer= ;* THIS GETS DOESNT GET REPEATED ANYMORE =);

      ht1.has_next(result: keep_processing);
      rc = ht1.find_next();
    end;
  end;

run;

Answer 2

You can solve it this way....but Rob's answer is better.

data results;

 %Macro NoDuplicate;
  Put auction_id= potential_buyer= ; * No Longer Duplicated;
 %Mend noduplicate;

 attrib potential_buyer length=$1;

 set auction;

 if _n_ eq 1 then do;
  declare hash ht1(dataset:'buyers', multidata: 'y');
  ht1.definekey('auction_id');
  ht1.definedata('potential_buyer');
  ht1.definedone();
  call missing (potential_buyer);
 end;

 **
 ** LOOP THROUGH EACH POTENTIAL BUYER AND PROCESS THEM
 *;
 if ht1.find() eq 0 then do;

  %NoDuplicate

  ht1.has_next(result: ht1_has_more);
  do while(ht1_has_more);
   rc = ht1.find_next();
   %NoDuplicate
   ht1.has_next(result: ht1_has_more);
  end;
 end;

run;