topic Re: POINT= option. Why does it need a variable? in SAS Procedures

POINT= option. Why does it need a variable?

Oliver2 — Thu, 25 Jun 2015 01:44:17 GMT

Hello!

I had a quick look, but couldn't find any questions similar to this, so hopefully I'm not bringing up old questions.

What is the reason the the POINT= option only works when set to a set to equal a variable (eg the obsnum below), rather than just setting it to equal an integer?

eg why does this work

data OJOSData;

obsnum=6;

set grades point=obsnum;

output;

stop;

run;

but this doesn't?

data OJOSData;

set grades point=6;

output;

stop;

run;

I was just wondering what the underlying reason is.

Many thanks

Oliver

PS the SAS University software is a godsend for testing things like this that puzzle me

Re: POINT= option. Why does it need a variable?

SASKiwi — Thu, 25 Jun 2015 01:55:05 GMT

There are already options for reading a specific observation or range of observations. FIRSTOBS= for the first record to be read and OBS= for the last record to be read.

POINT= is for identifying observations by formula/calculation.

data want;

set have (firstobs = 6 obs = 6);

run;

Re: POINT= option. Why does it need a variable?

Oliver2 — Thu, 25 Jun 2015 05:30:38 GMT

Right! It's interesting isn't it how certain rules work in certain ways.

With POINT you HAVE to use a variable, but with firstobs you CANNOT use a variable. At least I can't make it work...

data OJOSData;

fobs=7;

set grades (firstobs=fobs);

run;

Thanks SASKiwi, something for me to think about!

Re: POINT= option. Why does it need a variable?

SASKiwi — Thu, 25 Jun 2015 05:32:41 GMT

That's right - refer to the documentation for the correct use of each option.

Re: POINT= option. Why does it need a variable?

gergely_batho — Tue, 30 Jun 2015 13:15:08 GMT

obs= and firstobs= dataset options are designed to subset the data before it reaches the data step or a procedure. As they are data set options, they work almost in any circumstances. For example in a proc step. Obviously you don't have data step variables in a proc step. obs= and firstobs= can subset the observations very efficiently.

point= works only in a data step, it is an option of the set statement. It is designed to allow random/direct access to specific observations.

For example if you want to read the 10th, 20th and than again the 10th observation.