Identifying First encounter activity

[a_zacMD]

I want to be able to flag those individuals who have multiple encounters and a previous encounter falls within a certain group, but only if it happens within a specified time frame (I am able to calculate the time, I'm just trying to illustrate the relationship.)

Here is an example. For ID 1234 there are two encounters, where the first is a type 1 and the second encounter happened at day 7. How can I loop the second encounter back to the previous (7-Jul-2020) encounter to confirm that encounter is a type 1 and therefore should fall into the bucket?

I don't care about ID 5656 because none of them fall into type 1. 

ID	Date	Type	delta	Bucket
1234	7-Jul-20	1
1234	14-Jul-20	0	7	1
5656	7-Jul-20	0
5656	14-Jul-20	0	7
8879	7-Jul-20	0
8879	14-Jul-20	1	7
8879	21-Jul-20	0	7	1

Thank you in advance, 

[PeterClemmensen]

I think this is what you want

data have;
input ID Date $ Type delta Bucket;
infile datalines missover;
datalines;
1234 7-Jul-20  1    
1234 14-Jul-20 0 7 1
5656 7-Jul-20  0    
5656 14-Jul-20 0 7  
8879 7-Jul-20  0    
8879 14-Jul-20 1 7  
8879 21-Jul-20 0 7 1
;

data want;
   do until (last.id);
      set have;
      by id;
      if Type = 1 then flag = 1;
   end; 
   do until (last.id);
      set have;
      by id;
      output;
   end;
run;