Hi all the experts,
How do I find the earliest date within dateofadmin, dateofdrug and dateofmed for each ID using SAS code?
(ex. the earliest date for ID110 is dateofadmin14842 ((14842<18390 and ignore the ".")) )
and then i want to put the earliest in a new column :S
the date has been transfer into numeric format already.
However, i couldnt find the ways to compare numbers within columns :S
Please kindly give me a hint , would really be appreciated!
data want;
set have;
firstdate = .;
array datex {3} dateofadmin dateofdrug dateofmed;
do i=1 to 3;
if datex(i) ne . then do;
if firstdate = . then firstdate = datex(i);
else if datex(i) < firstdate then firstdate = datex(i);
end; end;
run;
The MIN function should ignore missing values:
earliest_date = min(dateofadmin, dateofdrug, dateofmed);
The min function accepts any number of arguments.
data want;
set have;
firstdate = min(dateofadmin, dateofdrug, dateofmed);
run;
thank you so much!
Now i have one more question
what if i wanna add one more column "where" is states where does the first date comes from?
like,
thank you 🙂
data want;
set have;
firstdate = .;
array datex {3} dateofadmin dateofdrug dateofmed;
do i=1 to 3;
if datex(i) ne . then do;
if firstdate = . then do;
firstdate = datex(i);
where = vname(datex(i));
end;
else if datex(i) < firstdate then firstdate = datex(i);
end; end;
run;
It's possible to shorten the code by a line or two using arrays, but this variation might be easier to understand.
data want;
set have;
earliest_date = min(dateofadmin, dateofdrug, dateofmed);
length varname $ 32;
if earliest_date > . then select (whichn(earliest_date, dateofadmin, dateofdrug, dateofmed));
when (1) varname='dateofadmin';
when (2) varname='dateofdrug';
when (3) varname='dateofmed';
end;
run;
Available on demand!
Missed SAS Innovate Las Vegas? Watch all the action for free! View the keynotes, general sessions and 22 breakouts on demand.
Learn how use the CAT functions in SAS to join values from multiple variables into a single value.
Find more tutorials on the SAS Users YouTube channel.