DIF function order

okaka23 — Thu, 31 May 2018 04:42:58 GMT

data four;
set two;
by x;
diff=dif(total);
if first.x then diff=.;
run;

Why i cannot put this way? any difference ? thanks

data four;
set two;
by x;

if first.x then diff=.;
diff=dif(total);
run;

Re: a quick question

Reeza — Thu, 31 May 2018 04:42:18 GMT

Order of operations. If you set it missing and then calculate it, it has a value.

If you calculate it, know it’s wrong then set to missing it’s fine, then it stays missing.

DIF like LAG is a queue function

https://www.lexjansen.com/phuse/2011/cc/CC08.pdf

@okaka23 wrote:

data four;
set two;
by x;
diff=dif(total);
if first.x then diff=.;
run;

Why i cannot put this way? any difference ? thanks

data four;
set two;
by x;

if first.x then diff=.;
diff=dif(total);
run;

topic Re: a quick question in SAS Programming

DIF function order

Re: a quick question