How to determine the length of an array?

Question

If I dont know the exact length of an array after a transpose, is there a way to output it? or to use it, without manually looking through the output data? For example, if I transpose on number of pills dispensed, but that number is variable for each 'id' and then I want to specify that array in a regression, is there a way to do it without finding the value via manual visual inspection?

PROC PHREG DATA=...;
ARRAY start{*} start1-start????;
DO I=1 TO ?????;
IF  start{I}<t2event THEN var=1;
END;
MODEL .........

As a corollary if I know that its less than say, 100, and I specify 100, would there be any consequence? Thanks!

Answer 1

The DIM() function returns the dimensions of an array. You can use the : suffix to make a variable list of names that start with the same letters.

 ARRAY start{*} start: ;
 DO I=1 TO dim(start);