topic Array to substitute in Date in SAS Programming

Array to substitute in Date

jdukes42 — Mon, 25 Jul 2011 18:47:20 GMT

Hi All,

I have a wide data set containing drug names and start dates.

For each individual I want to transfer the start dates for each drug into a new variable. In cases where the drug is the same I want to use the earliest date as the new start date. See example below .

How can this be done using an array?

	RX_1	RX_2	RX_3	Start_1	Start_2	Start_3	New_dt1	New_dt2	New_dt3
1	1	2	2	01/20/05	01/29/05	1/30/05	01/20/05	01/29/05	1/29/05
2	1	2	3	01/20/05	01/20/05	1/21/05	01/20/05	01/20/05	1/21/05

Thanks,

Jonathan

Array to substitute in Date

art297 — Mon, 25 Jul 2011 19:38:34 GMT

You don't really need arrays to do this, but you asked:

data want (drop=i j);

set have;

array old(*)Start_1-Start_3;

array drug(*)RX_1-RX_3;

array New_dt(3);

format New_dt1-New_dt3 mmddyy8.;

do i=1 to dim(old);

New_dt(i)=old(i);

do j=1 to i;

if drug(i) eq drug(j) then do;

New_dt(i)=min(New_dt(i),New_Dt(j));

New_dt(j)=New_dt(i);

end;

run;

Array to substitute in Date

jdukes42 — Mon, 25 Jul 2011 20:01:19 GMT

Art297,

Thank you for the swift reply and help.

Jonathan

Array to substitute in Date

data_null__ — Mon, 25 Jul 2011 23:48:56 GMT

I thought WHICHN function might be useful. But I probably don't understand the problem.

data have;

input id RX_1-RX_3 (Start_1-Start_3)(:mmddyy.);

array rx

rx_:;

array s

start_:;

array new[3];

do i = 1 to dim(rx);

new = s[whichN(rx,of rx

)];

end;

format start_: new: mmddyy.;

drop i;

cards;

1 1 2 2 01/20/05 01/29/05 1/30/05

2 1 2 3 01/20/05 01/20/05 1/21/05

;;;;

run;

proc print;

run;