last date from multiple columns

[SannaSanna]

Hi. 

Is there a data step that will help me determine the very last date for each patient below?

The table shows 4 patients each with dates under each olumn. I’m trying to write code that will look at

each of the columns (presc1-4) to determine the very last date and tell me the column header the date falls under?  

  example below:

PATIENT	PRESC1	PRESC2	PRESC3	PRESC4
D51841	5/16/2013	5/10/2012	6/1/2013	1/10/2000
D255	8/1/2011	3/5/2010	8/1/2011	5/6/2011
F27898	9/16/2000	3/6/1995	2/20/2014	7/1/1995

 Desired results:

PATIENT	date	type
D51841	1/10/2000	presc4
D255	8/1/2011	presc1 & presc3
F27898	2/20/2014	presc3

[Reeza · Accepted solution]

If you can have multiples it's a little more difficult but not too difficult.

Use an array with MAX(). Dates are stored as numbers, so the largest date is the largest number and the MAX function will tell you which date is the largest. VNAME() will return the name of the variable.

Untested:

data want;

set have;

length var_name $100.;

array pr(*) presc1-presc4;

max_date = max(of pr(*));

do i=1 to dim(pr);

if pr(i)=max_date then var_name = catx(" & ", var_name, vname(pr(i)));

end;

run;

[SannaSanna]

Ohh thank you so much Mr. Grand Advisor!!!  It even produced results where dates were the same in different columns.  I can flag those for further work.  thanks again!!  This SAS Support Cummunity bulletin is really the BEST

[Reeza]

Ms. Grand Advisor