SAS Chapter 10: Processing Macro Variables At Execution Time

Question 1

Which of the following is false?

Accepted Answer

Macro functions are always processed during the execution of the DATA step.

Answer

A %LET statement causes the macro processor to create a macro variable before the program is compiled.

Answer

To create a macro variable that is based on data calculated by the DATA step, you use the SYMPUT function.

Answer

Macro variable references in a DATA step are always resolved prior to DATA step execution.

Question 2

Which of the following correctly creates a macro variable named region and assigns to it a value that is based on the value of the data set variable Location?

Accepted Answer

data new;
   set sasuser.all;
   if location='Boston' then do;
      call symput('region', 'East');
   end;
   else do;
      call symput('region', 'West');
   end;
run;

Answer

data new;
   set sasuser.all;
   if location='Boston' then do;
      %let region=East;
   end;
   else
      %let region=West;
   end;
run;

Answer

data new;
   set sasuser.all;
   if location='Boston' then do;

call symput(region, "East");
   end;
   else
      call symput(region, "West");
   end;
run;

Answer

data new;
   set sasuser.all;
   if location='Boston' then do;
      symput(region, East);
   end;
   else
      symput(region, West);
   end;
run;

Question 3

The SYMPUT routine cannot

Accepted Answer

be used to assign a numeric value to a macro variable in an SCL program.

Answer

be used to assign a data set variable as a value to a macro variable.

Answer

create a series of macro variables in one DATA step.

Answer

automatically convert a numeric value to a character value when used to assign a value to a macro variable in a DATA step.

Question 4

Which of the following programs correctly creates a series of macro variables whose names are values of the data set variableCourse_code, then indirectly references one of those macro variables in a later step?

Accepted Answer

data _null_;
   set sasuser.courses;
   call symput(course_code, trim(course_title));
run;
%let crsid=C005;
proc print data=sasuser.schedule noobs label;
   where course_code="&crsid";
   var location begin_date teacher;
   title1 "Schedule for &&&crsid";
run;

Answer

data _null_;
   set sasuser.courses;
   call symput(course_code, trim(course_title));
%let crsid=C005;
proc print data=sasuser.schedule noobs label;
   where course_code="&crsid";
   var location begin_date teacher;
   title1 "Schedule for &c005";
run;

Answer

data _null_;
   set sasuser.courses;
   call symput('course_code', trim(course_title));
run;
%let crsid=C005;
proc print data=sasuser.schedule noobs label;
   where course_code="&crsid";
   var location begin_date teacher;
   title1 "Schedule for &&&crsid";
run;

Answer

data _null_;
   set sasuser.courses;
   call symget(course_code, trim(course_title));
run;

%let crsid=C005;
proc print data=sasuser.schedule noobs label;
   where course_code="&crsid";
   var location begin_date teacher;
   title1 "Schedule for &&&crsid";
run;

Question 5

Which of the following statements about the resolution of macro variable references is false?

Accepted Answer

If more than four consecutive ampersands precede a name token, the macro processor generates an error message.

Answer

Two ampersands resolve to one ampersand.

Answer

Re-scanning continues until there are no remaining macro triggers that the macro processor can resolve.

Answer

The macro processor always re-scans a name token that is preceded by multiple ampersands or by multiple percent signs.

Question 6

In which of the following situations would you use SYMGET rather than a macro variable reference (&macvar)?

Accepted Answer

all of the above

Answer

to create a DATA step variable from a macro variable value during the execution of the DATA step

Answer

to include a macro variable reference in a PROC SQL view

Answer

to access the value of a macro variable during the execution of an SCL program

Question 7

Which of the following correctly creates a macro variable in a PROC SQL step?

Accepted Answer

select fee/days format=dollar8.
into :daily_fee from sasuser.all;

Answer

call symput(daily_fee, put(fee/days, dollar8.);

Answer

%let daily_fee=put(fee/days, dollar8.)

Answer

select fee/days format=dollar8.
into daily_fee from sasuser.all;

Question 8

According to the global symbol table shown here, what value will a reference to &&teach&crs resolve to?

Accepted Answer

Forest, Mr. Peter

Answer

&TEACH3

Answer

TEACH3

Answer

none of the above

Question 9

Which of the following statements correctly creates a DATA step variable named Price and assigns to it the value of the macro variabledaily_fee during DATA step execution?

Accepted Answer

price=symget("daily_fee");

Answer

price=&daily_fee;

Answer

price=symget(daily_fee);

Answer

price=symget(&daily_fee);

Question 10

Which of the following is false?

Accepted Answer

PROC SQL automatically converts to a numeric value any macro variable value that you attempt to compare to a numeric value.

Answer

The SYMPUT routine can be used to create a macro variable during execution of the DATA step or during execution of an SCL program.

Answer

In the DATA step, the SYMPUT routine automatically converts to a character value any numeric value that you attempt to assign as the value of a macro variable.

Answer

In an SCL program, the SYMPUTN routine can be used to assign a numeric value to a macro variable.