topic Re: Assignments of visits based on date in SAS Programming

Assignments of visits based on date

sasg — Mon, 16 Jul 2018 15:28:22 GMT

Hi All,

I’m trying to assign visit names based on the

dates. Need help regarding logic. Using SAS 9.3.

i have dataset a, one record per member.

id Date

001 28jan2016

002 04feb2017

dataset b: multiple records per member.need to derive

visit value based on dataset a date value. Date-st is

before the date then visit values should be visit-1,visit-2

Etc...if Date-st is after the Date then visit values should be

visit+1 , visit+2 etc. Different number of visits per subject

. If Date-st is missing then need to use Date-ed to

assign visit.

id Date-st Date-ed Visit

001 27jan2016 29jan2017 Visit-1

001 28jan2016 29jan2017 Visit0

001 29jan2016 30jan2017 Visit+1

002 4feb2017 6feb2017 Visit0

002. 6feb2017 7feb2017 Visit1

002 8feb2017 9feb2017 Visit2

003 . 10feb2017 Visit3

As I just started on SAS, Need help me with the coding.thanks for your help.

Thanks in advane.

Re: Assignments of visits based on date

ballardw — Mon, 16 Jul 2018 16:44:18 GMT

Is there any real reason to include "visit" in the variable if the text is in every single value?

Also please confirm that your dates as SAS date valued numeric variables with a SAS date9. format applied.

Note that you have made things somewhat difficult by not giving us the names of the datasets and using variable names that by default are not valid for SAS variables (date-st date-ed, hyphens aren't normally valid SAS variables).

Also for id 002 you compare 04feb2017 with

Re: Assignments of visits based on date

sasg — Tue, 17 Jul 2018 02:02:19 GMT

Re: Assignments of visits based on date

PGStats — Tue, 17 Jul 2018 03:40:45 GMT

It can be done like this:

proc sort data=b; by id date_st date_ed; run;

data want;
length visit $10;
nn = 0;
do until (last.id);
    merge a b; by id;
    nn = nn - (coalesce(date_st, date_ed) < date);
    end;
do until (last.id);
    merge a b; by id;
    if coalesce(date_st, date_ed) = date then nn = 0;
    visit = cats("Visit", nn);
    output;
    nn = nn + 1;
    if nn = 0 then nn = 1; /* Skip visit0 if date is not found */
    end;
drop nn;
run;

Re: Assignments of visits based on date

sasg — Tue, 17 Jul 2018 20:06:56 GMT

Thanks for your reply.