topic Summing only negative values of a certain variable in SAS Procedures

Summing only negative values of a certain variable

carbs — Mon, 02 Apr 2012 08:58:49 GMT

I have monthly data on variable x across 20 countries and would like to sum only the negative values of the variable per month. I've used the code below to sum all of the monthly observations across 20 countries together, and would like to know how to modify the code to get it to sum only the negative values.

data want;

set have;

by date;

if first.date then total=0;

total+x;

if last.date then output;

run;

thanks in advance..

Summing only negative values of a certain variable

Gerd47 — Mon, 02 Apr 2012 09:04:33 GMT

Try this

data have;

input date x;

cards;

1 3

1 -3

1 -4

2 4

2 -2

2 -7

;

run;

data want;

set have;

by date;

if first.date then total=0;

if x<0 then total+x;

if last.date then output;

run;

Summing only negative values of a certain variable

Haikuo — Mon, 02 Apr 2012 11:18:07 GMT

Or use (where=) to make it more efficient in this case:

data want;

set have(where=(x<0));

by date;

if x<0;

if first.date then total=0;

if x<0 then total+x;

if last.date then output;

run;

Regards,

Haikuo

Re: Summing only negative values of a certain variable

Linlin — Mon, 02 Apr 2012 12:17:24 GMT

more efficient:

data want;

set have(where=(x<0));

by date;

if first.date then total=0;

total+x;

if last.date then output;

run;

Re: Summing only negative values of a certain variable

Haikuo — Mon, 02 Apr 2012 12:28:50 GMT

LOL, I don't know what I am doing. Guess I just added (where=) to his/her code harmlessly and more important, effortlessly. Linlin, thanks for pointing that out.

Haikuo

Re: Summing only negative values of a certain variable

Howles — Mon, 02 Apr 2012 20:06:53 GMT

I don't know if efficiency is a concern. I do know that the WHERE approach will not generate an observation for a month with no negatives. That may or may not be desired.

Linlin wrote:
more efficient:
data want;
set have(where=(x<0));
by date;
if first.date then total=0;
total+x;
if last.date then output;
run;

Summing only negative values of a certain variable

carbs — Mon, 02 Apr 2012 21:39:14 GMT

Thanks for the quick and correct answers!