Question re for loops

george_1 — Sat, 14 Dec 2013 03:40:18 GMT

Hi,

I have a fairly large data set (around 1 million observations) that looks something like the following table:

ID n P y

1 5 11.4 0.04

2 8 7.6 0.02

3 13 12.2 0.01

4 4 3.9 0.07

...

I want to create a column D that calculates the following for each row: P * [ (1+y)^0 + (1+y)^1 + (1+y)^2 + ... + (1+y)^n ]

I tried using a for loop but wasn't able to perform the required calculation. Any help would be much appreciated.

Thanks

Re: Question re for loops

Tom — Sat, 14 Dec 2013 04:35:35 GMT

Seems like a simple problem. If N gets too big you might have problems with numeric overflow.

data have;

input ID n P y @@;

cards;

1 5 11.4 0.04 2 8 7.6 0.02 3 13 12.2 0.01 4 4 3.9 0.07

run;

data want ;

set have ;

d = 0;

do i=0 to n ;

d=d+(1+y)**i;

end;

d = p*d;

drop i ;

run;

Obs ID n P y d

1 1 5 11.4 0.04 75.616

2 2 8 7.6 0.02 74.135

3 3 13 12.2 0.01 182.359

4 4 4 3.9 0.07 22.428