compare row values

[sai_kumar]

hi experties
i struck at a point how to compare two different row values
for example
input is like below

A B

1 2

2 3

3 4

5 6

6 7

4 5

7 .

then after modification, I want to see

A B C D E F G
1 2 3 4 5 6 7
2 3 4 5 6 7
3 4 5 6 7
5 6 7
6 7
7 .
4 5 6 7
please help me in this situation how can i write code

[novinosrin]

Hi @sai_kumar  Welcome to SAS communities. Can you plz explain at point you are stuck and also how you want to compare across rows?

I'd assume the output order to be the same as input order like

4 5 6 7

7 .

rather than

7 .
4 5 6 7

[sai_kumar]

please ignore the output order

just i want compare the column2 value with the column1 values

if column2 value is available in column1 values then column3 have to be prepare with the column2 value of the column 1 value

like
A B
1 2
2 4
4 7

in the above example i want compare B value 2
in the column A
value 2 is available in the column A
so then i want create column3 like C
so ouput would be
A B C
1 2 4
after completion of all columnB values comparition

again i want compare columnC values with columnA

and create columnD

and soo on until end

[novinosrin]

Hi @sai_kumar  Pardon me as I wrote the below code before I saw your response to my previous post. It seems to be the below logic should be close to your requirement

data have;
input A B;
cards;
1 2
2 3
3 4
5 6
6 7
4 5
7 .
;

data want;
set have;
array t(6);
 if _n_=1 then do;
 if 0 then set have(rename=(b=_b));
   dcl hash H (dataset:'have(rename=(b=_b))') ;
   h.definekey  ("a") ;
   h.definedata ("_b") ;
   h.definedone () ;
end;
k=b;
do until(_b=.);
 rc=h.find(key:k);
 n=sum(n,1);
 t(n)=_b;
 k=_b;
end;
drop k _b rc n;
run;

[Ksharp]

It is called SEARCHING TREE problem .

data have;
input _start $ _end $;
cards;
1 2
2 3
3 4
5 6
6 7
4 5
7 .
;
run;
 
data want(keep=path);
if _n_ eq 1 then do;
length path _path  $ 800 ;
if 0 then set have;
declare hash ha(hashexp:20,dataset:'have(where=(_start is not missing and _end is not missing))',multidata:'y');
ha.definekey('_start');
ha.definedata('_end');
ha.definedone();

declare hash pa(ordered:'y');
declare hiter hi_path('pa');
pa.definekey('n');
pa.definedata('n','path');
pa.definedone();

end;


set have;
count=1;n=1;_n=1;
path=catx('|',_start,_end);
   
pa.add();
do while(hi_path.next()=0);
 if n ne 1 then pa.remove(key:_n);_n=n;
 _path=path;   
 _start=scan(path,-1,'|');
 rc=ha.find();   if rc ne 0 then output; 
 do while(rc=0);
  if not findw(path,strip(_end),'|') then do;
   if length(path)+length(_end)+1 gt lengthc(path) then do;
    putlog 'ERROR: The length of path and _path are set too short';
    stop;
   end;
   
   count+1;n=count;
   path=catx('|',path,_end);
   pa.add();
   path=_path;
 end;   else output; /* It is a circle.*/
  rc=ha.find_next();
end;
end;
pa.clear();

run;