How to sum selected array variables

[s100]

Header 1	Header 1	Header 2	Header 3	Header 4	Header 5	Header 6	Header 7	Header 8	Header 9	Header 10	Header 11	Header 12	Header 13
id	cost1	cost2	cost3	cost4	cost5	cost6	cost7	cost8	cost9	cost10	cost11	cost12	end
1	.	0	1	1	4	6	7	2	8	2	8	0	5
2	1	1	.	1	2	2	2	2	3	5	7	6	2
3	0	0	0	0	0	0	0	0	0	0	1	1	10
4	2	2	2	2	2	2	2	2	2	2	2	2	12

My dataset looks like this. Now, I want to add a new column to get the sum of selected "costXX" variables from 1 to the value of end. For example, I should sum up cost1-cost5 for the first row and cost1-cost12 for the last row. The value of costXX variables could be missing.

I created an array for these variables: array a(12) cost1-cost12. But the sum function can only be used for sum up all of the array variables, right?  tot = sum(of a{*} );

Any one know how to do this?

Thanks!

[PGStats · Accepted solution]

You need an array indeed, but a DO loop as well :

data want;

set have;

array cost{*} cost1-cost12;

do _n_ = 1 to end;

     mySum = sum(mySum, cost{_n_});

     end;

run;

PG

[s100]

Thank you! It works!!