topic Re: DO statements missing semicolon in SAS Programming

DO statements missing semicolon

minitt01 — Tue, 29 Nov 2016 21:06:14 GMT

Do statement needs a semicolon as below.

DO;

SAS satement ;

END;

But recently, I happend to omit the semicolon next to DO statement and it still works and generated the same results as with semicolon. Does that mean that I don't have to worry about the semicolon for DO statement?

Thank you in advance for your help.

Re: DO statements missing semicolon

Reeza — Tue, 29 Nov 2016 21:18:59 GMT

It depends. What kind of code did you have after DO?

You can include certain statements after a DO that control the loop.

And others will generate an error.

In fact, I'd say it's unusual to see just a DO, it would be something like

if x=1 then do;

Do i=1, 2, 3 6;

http://support.sas.com/documentation/cdl/en/lestmtsref/69738/HTML/default/viewer.htm#p1cydk5fq0u4bfn1xfbjt7w1c7lu.htm

Re: DO statements missing semicolon

mkeintz — Tue, 29 Nov 2016 21:22:09 GMT

I guess what your are really asking is: SAS appears to not object in certain cases when you forget to terminate the DO statement with a semi-colon. And in those cases, if SAS doesn't object, can you be sure the result will be the same as it would be with the semi-colon in place?

I don't know, but I wouldn't trust it.

At the moment, I can't think of a counterexample.

For instance these two support the "no difference" conjecture, but that's not proof:

do;

x=1;

y=3*x;

end;

and

x=1;

y=3*x;

end;

regards,

Mark

Re: DO statements missing semicolon

Astounding — Tue, 29 Nov 2016 21:37:09 GMT

The key to removing the semicolon is that the result has to create a valid DO statement. So if the next statement is:

name='Fred';

That works, because this would be a valid DO loop:

do name='Fred';

It both sets NAME to "Fred" and performs any additional statements within the loop.

But if the next statement wouldn't form a valid DO statement, you will get an error. A few examples where omitting the semicolon gives you an error because the resulting DO statement is no longer correct syntax:

if name='Fred' then salary='High';

substr(name, 4,1)='t';

select (name);

array names {1} name;

retain total 0;

Re: DO statements missing semicolon

mkeintz — Tue, 29 Nov 2016 22:00:11 GMT

Yes, but in your example ("do if ...."), SAS would send an error message, thereby protecting the programmer from the oversight.

I think the OP's issue is: if there's no such error message, can there ever be a difference in results attributable to the missing semi-colon?

M K

Re: DO statements missing semicolon

Astounding — Wed, 30 Nov 2016 00:44:10 GMT

Well, I had a chance to think about this on the ride home. If that's the question, I think you're right. The closest I could imagine was this:

data testing;

before = time();

do i=1 to 10000000;

do after = time();

end;

diff = after - before;

run;

Compare that with the added semicolon:

data testing2;

before = time();

do i=1 to 10000000;

do;

after = time();

end;

diff = after - before;

run;

Now if for some reason the programs differ in their execution time, DIFF would change. Even so, that's a lot of imagination with zero practicality.

Re: DO statements missing semicolon

minitt01 — Wed, 30 Nov 2016 14:19:45 GMT

Thank you for your opinion.

Yes, it was in IF/THEN statement. I was expecting an error message but there was not. That's why I was confused.

Let me try it with some other data and see how it works.

Thank you again,

Re: DO statements missing semicolon

minitt01 — Wed, 30 Nov 2016 14:22:54 GMT

Thank you for your attention on this topic.

Yes, I was confused cuz it didn't give me any error message and generated the same result.

I don't know why this still works.. need to search more.

Thank you again,

Re: DO statements missing semicolon

minitt01 — Wed, 30 Nov 2016 14:45:09 GMT

Thank you for your opinion.

Yes I expected an error message but it runs without error message.

I thought that SAS code is very sensitive on Semicolon and operators.

I need to search little more detail about this.

Thank you again,