topic Re: How to count consecutive days? in New SAS User

How to count consecutive days?

juliajulia — Tue, 26 Feb 2019 19:16:01 GMT

Hello,

i have a data set with id and service date and i want to know if each service date are 6 month apart or not. i use the lag function but it give me a weird result. Please help me figure out how this works. thank you so much.

data test1;
set test;
by id;
if first.id then date=.;
else date = lag(servicedate);
format date mmddyy10.;
run;

id	Count	servicedate	year
1	0	11/8/2013	2013
1	20	11/7/2014	2014
1	20	2/2/2015	2015
1	20	4/23/2015	2015
1	0	10/8/2015	2015
1	0	1/5/2016	2016
1	20	4/6/2016	2016
1	40	6/30/2016	2016
2	20	8/21/2015	2015
2	20	8/21/2015	2015

Re: How to count consecutive days?

PaigeMiller — Tue, 26 Feb 2019 19:18:23 GMT

data test1;
set test;
by id;
prev_date=lag(servicedate);
if first.id then date=.;
else date = prev_date;
format date mmddyy10.;
run;

Re: How to count consecutive days?

juliajulia — Tue, 26 Feb 2019 21:30:22 GMT

Thanks.

i found my question is more complicated than i thought. i actually need to find those dates that has 6 month or greater interval with any of the previous date value. for example, the value of the newDate variable only keep those dates that have 6 month or greater than any of the previous dates in the servicedate. How to create the newDate variable? please help.

ID	servicedate	NewDate
1	11/8/2013	11/8/2013
1	12/7/2013
1	2/2/2014	2/2/2014
1	4/23/2014
1	9/8/2014	9/8/2014
1	12/5/2014
1	4/6/2015	4/6/2015
2	3/17/2016	3/17/2016
2	4/17/2016
2	9/18/2016	9/18/2016
2	12/5/2016
2	12/9/2016
2	4/9/2016	4/9/2016
2	11/21/2016	11/21/2016
2	11/21/2016

Re: How to count consecutive days?

andreas_lds — Wed, 27 Feb 2019 12:17:18 GMT

Sorry, but i can't understand the logic you have described. Why is "4/23/2014" not in the NewDate variable? There are observations with id=1 having a difference of more than six months-

@juliajulia wrote:

Thanks.

i found my question is more complicated than i thought. i actually need to find those dates that has 6 month or greater interval with any of the previous date value. for example, the value of the newDate variable only keep those dates that have 6 month or greater than any of the previous dates in the servicedate. How to create the newDate variable? please help.

ID servicedate NewDate

1 11/8/2013 11/8/2013

1 12/7/2013

1 2/2/2014 2/2/2014

1 4/23/2014

1 9/8/2014 9/8/2014

1 12/5/2014

1 4/6/2015 4/6/2015

2 3/17/2016 3/17/2016

2 4/17/2016

2 9/18/2016 9/18/2016

2 12/5/2016

2 12/9/2016

2 4/9/2016 4/9/2016

2 11/21/2016 11/21/2016

2 11/21/2016

Re: How to count consecutive days?

PaigeMiller — Wed, 27 Feb 2019 12:48:07 GMT

data test1;
    set test;
    by id;
    prev_date=lag(servicedate);
    if not first.id and intck('month',prev_date,servicedate,'c')>=6
        then newdate=date;
    format newdate mmddyy10.;
run;

Use the INTCK function to determine how many months have elapsed between the two dates.

I note, as did @andreas_lds that your word description does not match the output you say you want.