Number of Continuous Days

[sas33]

Hi,

i want to calculate  Continuous days on a drug by id.

if the days difference between previous end date  & next start date <= 7 days then it is considered as continuous.

ID	begin date	end date
1001	2/6/2019	2/12/2019
1001	3/13/2019	3/18/2019
1002	4/4/2019	4/10/2019
1002	4/20/2019	5/12/2019
1002	7/11/2019	7/20/2019
1002	8/6/2019	8/20/2019
1002	8/17/2019	9/5/2019
1002	8/30/2019	9/13/2019
1003	11/7/2019	11/13/2019
1003	11/15/2019	12/14/2019
1003	12/31/2019	1/14/2020

Result data set 

ID	begin date	end date	Days Diff from Prev end date	Continuous Days
1001	2/6/2019	2/12/2019	.	7
1001	3/13/2019	3/18/2019	29	6
1002	4/4/2019	4/10/2019	.	7
1002	4/20/2019	5/12/2019	10	23
1002	7/11/2019	7/20/2019	60	10
1002	8/6/2019	8/20/2019	17	15
1002	8/17/2019	9/5/2019	-3	31
1002	8/30/2019	9/13/2019	-6	38
1003	11/7/2019	11/13/2019	.	7
1003	11/15/2019	12/14/2019	2	37
1003	12/31/2019	1/14/2020	17	15

Thanks

[novinosrin]

HI @sas33 

data have;
input ID	(begindate	enddate) (:mmddyy10.);
format begindate	enddate mmddyy10.;
cards;
1001	2/6/2019	2/12/2019
1001	3/13/2019	3/18/2019
1002	4/4/2019	4/10/2019
1002	4/20/2019	5/12/2019
1002	7/11/2019	7/20/2019
1002	8/6/2019	8/20/2019
1002	8/17/2019	9/5/2019
1002	8/30/2019	9/13/2019
1003	11/7/2019	11/13/2019
1003	11/15/2019	12/14/2019
1003	12/31/2019	1/14/2020
;

data want;
 _n_=.;
 do until(last.id);
  set have;
  by id;
  Continuous =enddate-begindate+1;
  if _n_ then daysdiff=begindate-_n_;
  _n_=enddate;
  output;
 end;
run;

[sas33]

Hi, i don't think you have considered 7 day difference logic to be considered as continuous. Please see the highlighted rows in blue.

[novinosrin]

My sincere apologies for overlooking that part. Let me revisit the thread 

[novinosrin · Accepted solution]

Hi @sas33  Please see if the revised one helps

data want;
 _n_=.;
 do until(last.id);
  set have;
  by id;
  if first.id then _b=begindate;
  if _n_ then daysdiff=begindate-_n_;
  if  daysdiff>7 then _b= begindate;
  Continuous =enddate-_b+1;
  _n_=enddate;
  output;
 end;
 drop _:;
run;

[sas33]

Thank you so much, this works perfect.