CODEWITHSUNDEEP
sas
smackersz88
smackersz88

Reputation: 93

Renaming date variable to perform an intck to calculate day difference

I have this dataset and need to calculate the days' difference between each dose date per period. How do I label each period study date so I can carry out an intck to calculate the days' difference per subject (ptno)

dataset

Upvotes: 1

Views: 116

Answers (2)

Wilson Jimenez
Wilson Jimenez

Reputation: 60

The code of Tom works very well. I simulated the data set with a few rows based in the sample showed above and it's OK. Only thing absent is PROC SORT. If the data set is huge the log will exhibit an error.

proc sort data=have;
   by ptno period;
run;

Upvotes: 1

Tom
Tom

Reputation: 51611

Just use the DIF() function to calculate the change in value for your date variable. SAS stores dates as number of days so the difference will be the number of days between the two observations. You could then test if the difference is 7 days or not.

data want;
   set have;
   by ptno period;
   interval = dif(ex_stadt);
   if first.ptno then interval=0;
   seven_days = (interval = 7) ;
run;

Upvotes: 3

Related Questions