topic Re: Gap of at least 30 days in SAS Programming

Gap of at least 30 days

div44 — Tue, 24 Jan 2017 06:01:55 GMT

Person	Chocolate	Date Received	Date Finished	No chocolate	Actual No chocolate
1	Snickers	7-May-15	11-May-15	0	0
1	MM	8-May-15	13-May-15	0	0
1	Twix	10-May-15	18-May-15	0	0
1	Bounty	12-May-15	16-May-15	0	0
1	Hersheys	17-Jun-15	21-Jun-15	1	0

I need to find when there were at least 30 days without a chocolate for person 1. My current code sorts the data by date received, and gets me the solution to "No chocolate". This is wrong, as it marks the last row as 1, suggesting a difference between (date finsihed - date received for the next chocolate) is 16May15 - 17jun15 = 31 days, however the code does not account for the Bounty choclate date finished which is 18May15, and hence the difference should have been 18May15 - 17Jun15 = 29days and hence does not meet the criteria of at least 30 days as suggested by the Actual No Chocolate column.

Sorting the data by date finshed descending does not help either

Any help would be appreciated thanks

Code

data want;

set have

by person date_received;

gap=date_received-lag(date_finished);

if first.person=1 then no_chocolate=1;

else if gap>=30 then no_chocolate+1;

run;

Re: Gap of at least 30 days

PeterClemmensen — Tue, 24 Jan 2017 07:51:02 GMT

I dont see that the Date finished for the Bounty is 18May15? Isn't that the date finished for the Twix?

Re: Gap of at least 30 days

DanielSantos — Tue, 24 Jan 2017 08:29:07 GMT

Hi.

Your code should work, Date Finished of Bounty is 16-May-2015.

data want;

set have

by person date_received;

gap=date_received-lag(date_finished);

if first.person=1 then no_chocolate=1;

else if gap>=30 then no_chocolate+1;

run;

Bear in mind that if you want to count exclusively the days between to dates you need to adjust by subtracting one day:

For example, if date_received=17-may-2015 and date_finished=16-may-2015, former minus the latter would return 1 day, is that the expected result? maybe you are looking for something like this:

gap=date_received-lag(date_finished)-1;

Hope it helps.

Daniel Santos @ www.cgd.pt;

Re: Gap of at least 30 days

Jagadishkatam — Tue, 24 Jan 2017 08:39:51 GMT

please try the sql code,

data have;
infile cards missover;
input Person	Chocolate$	Date_Received:date9.	Date_Finished:date9.;
format date: date9.;
cards;
1	Snickers	7-May-15	11-May-15	
1	MM	        8-May-15	13-May-15	
1	Twix	    10-May-15	18-May-15	
1	Bounty	    12-May-15	16-May-15	
1	Hersheys	17-Jun-15	21-Jun-15	
;

proc sql;
create table test as select a.*, b.Date_Received as other_rec, b.Date_Finished as other_fini,a.Date_Received-b.Date_Finished as day, b.Chocolate as choc from have as a, 
(select Chocolate,person, Date_Received, Date_Finished from have) as b where a.person=b.person;
quit;

Re: Gap of at least 30 days

Kurt_Bremser — Tue, 24 Jan 2017 10:04:17 GMT

data have;
infile cards missover;
input Person	Chocolate$	Date_Received:date9.	Date_Finished:date9.;
format date: date9.;
cards;
1 Snickers 7-May-15 11-May-15
1 MM 8-May-15 13-May-15
1 Twix 10-May-15 18-May-15
1 Bounty 12-May-15 16-May-15
1 Hersheys 17-Jun-15 21-Jun-15
1 Milka 31-aug-15 05-sep-15
;
run;

data want;
set have;
by person;
retain max_finish;
no_chocolate = 0;
if not first.person
then do;
  if date_received - max_finish > 30
  then no_chocolate = 1;
end;
max_finish = max(max_finish,date_finished);
run;

I added an additional data line to make sure that a value of 1 for no_chocolate is triggered.

Re: Gap of at least 30 days

div44 — Tue, 24 Jan 2017 17:44:40 GMT

Yes, it should have been the finished date for Twix.

Thanks for pointing that out.

Re: Gap of at least 30 days

div44 — Tue, 24 Jan 2017 17:45:58 GMT

The finished date for Twix is what I was looking for which is 18May, and it is here that the code collapses

Re: Gap of at least 30 days

Kurt_Bremser — Tue, 24 Jan 2017 19:45:03 GMT

Run my code. If it doesn't do what you want, post the modified example data step, and where the result differs from your expectations.