Continual Matching of Records

[adornodj]

I have a data set where I want to find all related records, and provide an ID to group them together.  I think an array, or some kind of loop, but I'm not 100% certain the way to go.  Below is an example on what I am looking to do.  

ID      Corresponding_Match

1        X

2        1

3         Y

4        Z

5       2

6       3 

In this example, record 1,2, and 5 would be my first related group; record 3 and 6 would also group together.   Ideally, each grouping would get a unique ID corresponding to them.  For example 1,2,5 would be UNIQUE1 and 3,6 would be UNIQUE2.  I'm operating on SAS EG with no additional add-ons or licenses other than the base package.  Any help is appreciated.  Thank you!

[Reeza · Accepted solution]

These are all very similar to your question. Do any of them work for you?

https://communities.sas.com/t5/SAS-Data-Management/Recursive-Query/m-p/466861

https://communities.sas.com/t5/SAS-Data-Management/recursive-joins-with-PROC-SQL/m-p/411824

https://communities.sas.com/t5/SAS-Programming/Recursive-lookup-for-ID-s/m-p/259635

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@adornodj wrote:

I have a data set where I want to find all related records, and provide an ID to group them together.  I think an array, or some kind of loop, but I'm not 100% certain the way to go.  Below is an example on what I am looking to do.  

ID      Corresponding_Match

1        X

2        1

3         Y

4        Z

5       2

6       3 

In this example, record 1,2, and 5 would be my first related group; record 3 and 6 would also group together.   Ideally, each grouping would get a unique ID corresponding to them.  For example 1,2,5 would be UNIQUE1 and 3,6 would be UNIQUE2.  I'm operating on SAS EG with no additional add-ons or licenses other than the base package.  Any help is appreciated.  Thank you!

---

[adornodj]

I'm testing some code someone created from the 3rd link you provided me.  if that does not work, I'll post a follow up.  Thank you!  Now that I know it's a "recursive match" that helps greatly.  

[adornodj]

Hi All - the 3rd link has code that worked to solve my problem.  On my full dataset, I had records where the ID2 was blank (see below).  I wound up setting those values equal to ID1, and that created clusters which were either 1 record (no matches), 2 matches (natural pair) or 3+ records within the cluster (which are outliers in my data).  

Thanks to all who provided assistance.  

HAVE

ID1 ID2

1   

2      Y

Y      Z

HAVE_UPDATED

ID1  ID2

1   1

2   Y

Y   Z

[Ksharp]

data have;
infile cards ;
input from $  to $ ;
cards;
1        X
2        1
3         Y
4        Z
5       2
6       3 
;
run;
data full;
  set have end=last;
  if _n_ eq 1 then do;
   declare hash h();
    h.definekey('node');
     h.definedata('node');
     h.definedone();
  end;
  output;
  node=from; h.replace();
  from=to; to=node;
  output;
  node=from; h.replace();
  if last then h.output(dataset:'node');
  drop node;
run;


data want(keep=node household);
declare hash ha(ordered:'a');
declare hiter hi('ha');
ha.definekey('count');
ha.definedata('last');
ha.definedone();
declare hash _ha(hashexp: 20);
_ha.definekey('key');
_ha.definedone();

if 0 then set full;
declare hash from_to(dataset:'full(where=(from is not missing and to is not missing))',hashexp:20,multidata:'y');
 from_to.definekey('from');
 from_to.definedata('to');
 from_to.definedone();

if 0 then set node;
declare hash no(dataset:'node');
declare hiter hi_no('no');
 no.definekey('node');
 no.definedata('node');
 no.definedone();
 

do while(hi_no.next()=0);
 household+1; output;
 count=1;
 key=node;_ha.add();
 last=node;ha.add();
 rc=hi.first();
 do while(rc=0);
   from=last;rx=from_to.find();
   do while(rx=0);
     key=to;ry=_ha.check();
      if ry ne 0 then do;
       node=to;output;rr=no.remove(key:node);
       key=to;_ha.add();
       count+1;
       last=to;ha.add();
      end;
      rx=from_to.find_next();
   end;
   rc=hi.next();
end;
ha.clear();_ha.clear();
end;
stop;
run;

[Ksharp]

If you have SAS/OR ,try this one:

/* Same code as SAS/OR */
proc optnet data_links=have out_nodes=want GRAPH_DIRECTION=UNDIRECTED;
data_links_var from=from to=to;
concomp;
run;

[adornodj]

Hello thank you for the response.  I am testing out the logics today.  Very grateful to the code you all have sent me.  Truly.