topic Re: How do I take previous observation if observation with certain date is missing? in SAS Programming

How do I take previous observation if observation with certain date is missing?

Pascal1 — Mon, 01 Oct 2018 13:10:40 GMT

Hello guys,

I have a dataset with some variables of which one is the date.

My problem is that I want to create a subset with a certain period between dates.

The program should take a given date minus a number of previous observations.

Like I have 30. Mar 2001 and I want to create the subset with the observations: 30. Mar 2001 - 260 observations till 30. Mar 2001 - 11 observations.

I tried to set the period with

where date between '30mar2001'd-260 and '30mar2001'd-11;

but this will only work if there is a observation for every date.

SAS 9.4

Hope you can help.

Thanks a lot!

Regards,

Pascal

Kurt_Bremser — Mon, 01 Oct 2018 13:27:06 GMT

Please provide example data (in a data step with datalines, see my footnotes), and what the result from that should be.

Astounding — Mon, 01 Oct 2018 13:39:45 GMT

While your question is not particularly clear, here is an approach you can tailor to your needs.

proc sort data=have out=subset;

by descending date;

where date <= '30mar2001'd;

run;

data want;

set subset;

**** Now you can add your own logic here that depends on the date and/or

_N_ which will number the observations beginning with March 30 having _N_=1. ;

run;