topic Re: Calculating cumulative sum in SAS Data Management

Calculating cumulative sum

ilikesas — Thu, 11 Dec 2014 04:12:56 GMT

Hi,

my question might be too simple but I actually have some trouble figuring it out...

what I want to do is to calculate the cumulative sum of a column, so if I have the following table:

value
10
20
30
40

I would like to add to it the following column:

cummulative sum
10
30
60
100

Thank you

Re: Calculating cumulative sum

Reeza — Thu, 11 Dec 2014 04:19:35 GMT

data want;

set have;

retain cum_sum;

cum_sum+value;

run;

Re: Calculating cumulative sum

ilikesas — Thu, 11 Dec 2014 04:52:42 GMT

Hi Reeza,

thanks for the answer!

It is really short but I couldn't figure it out because its not so intuitive (at least to me) because I was trying to do something like setting the first cumsum to the value itself and for the rest of values to make cumsum by adding the value to the sum( ) of the previous values and I was getting a mess...

Re: Calculating cumulative sum

Reeza — Thu, 11 Dec 2014 05:05:06 GMT

Technically you don't even need the retain statement, the + implies the retain so the following works as well:

data want;

set have;

cum_sum+value;

run;

Re: Calculating cumulative sum

ilikesas — Thu, 11 Dec 2014 05:06:44 GMT

Hi Reeza its me again,

now I would like to add another level of complexity, if I may:

assume that in the previous case I had to calculate the cumulative sum for one company, but now I need to do the same thing but for many companies, so each time I get to a new company the cumulative sum restarts calculating.

Thank you

Re: Calculating cumulative sum

stat_sas — Thu, 11 Dec 2014 05:51:53 GMT

Hi,

For many companies you need by processing. Just make sure data is sorted by company variable.

data want;

set have;

by company;

if first.company then cum_sum=0;

cum_sum+value;

run;