topic Why two consecutive semicolons are needed? in SAS Procedures

Why two consecutive semicolons are needed?

bncoxuk — Tue, 12 Jul 2011 14:00:15 GMT

Hi sir,

I just run a macro as below. The macro is used to merge multiple datasets. The %else statement needs two consecutive semicolons ';' here. Otherwise, SAS reported that it cannot find the data. The log message shows that:

DATA work.model;

MPRINT(DOMERGE): SET work.model work.data05 RUN;

So it does miss a semicolon here.

/*The macro program as below*/

%let num=16;

%macro domerge;

%do i=1 %to &num;

DATA work.model;

%if &i=1 %then %do;

SET work.data01 work.data02;

%end;

%else SET work.model work.data%sysfunc(putn(&i+1.,z2.));;

RUN;

%end;

%mend domerge;

%domerge

Why two consecutive semicolons are needed?

data_null__ — Tue, 12 Jul 2011 14:09:48 GMT

The first one goes with the %ELSE the second one is emitted unconditionally and works as a null statement when &i eq 1 and when &i ne 1 it happens to provide the necessary semicolon for the SET emitted by %ELSE.

I usually almost always use %DO; code %end; as you have with %IF. I find it easier to understand as in this situation.

Why two consecutive semicolons are needed?

bncoxuk — Tue, 12 Jul 2011 14:16:23 GMT

Hi data_null_,

Can I kow why there need to be two separate semicolons for %ELSE and SET, rather than a single semicolon for a statement.:smileyconfused:

Re: Why two consecutive semicolons are needed?

data_null__ — Tue, 12 Jul 2011 14:43:44 GMT

Because BOTH statements (%else and SET) need semicolons.

Alternatively;

%else %str(set ...; );

Why two consecutive semicolons are needed?

DouglasMartin — Tue, 12 Jul 2011 19:02:19 GMT

Remember that what a macro statement generates need not be a complete SAS statement. So, in the case of your %ELSE you need to do two completely distinct things - finish the %ELSE statement and finish the SET statement. With only a single semicolon SAS can't tell that your SAS statment is finished because the semicolon has already been used to finish the %ELSE.

Why two consecutive semicolons are needed?

FloydNevseta — Thu, 14 Jul 2011 01:37:45 GMT

data_null_ gave you the answer to your question. If it's too confusing you could write the %else with %do...%end as you did for the %if statement, such as:

%else %do:

SET work.model work.data%sysfunc(putn(&i+1.,z2.));

%end;

That eliminates the consecutive semicolons and your confusion.

bncoxuk wrote:

Hi data_null_,

Can I kow why there need to be two separate semicolons for %ELSE and SET, rather than a single semicolon for a statement.