Copyright © 2008, SAS Institute Inc. All rights reserved. SAS ® Macros: Top-Five Questions (and Answers!) Kim Wilson –Technical Support Analyst SAS Institute Inc.

Copyright © 2008, SAS Institute Inc. All rights reserved. Q: Can you use SAS functions within the macro facility?

Copyright © 2008, SAS Institute Inc. All rights reserved. A: %SYSFUNC Macro Function The %SYSFUNC macro function enables you to execute SAS functions as well as user-written functions. In the following example, %SYSFUNC enables you to execute the DATE function: %put %sysfunc(putn(%sysfunc(date()),worddate20.)); This %PUT statement generates the following output: 95 %put %sysfunc(putn(%sysfunc(date()),worddate20.)); February 10, 2009

Copyright © 2008, SAS Institute Inc. All rights reserved. Q: What quoting function should I use to mask special characters such as the ampersand, percent sign, parentheses, and quotation marks?

Copyright © 2008, SAS Institute Inc. All rights reserved. A: Compile-Time Quoting Functions or Execution-Time Quoting Functions To mask special characters, one of the following types of quoting functions is required. Which type of quoting function you use depends on the situation:  Compile-time quoting functions: %STR–masks commas, mnemonics, and unmatched quotation marks and parentheses %NRSTR–masks percent signs and ampersands  Execution-time quoting functions: %BQUOTE–masks special characters and mnemonics in resolved values during macro execution %SUPERQ–masks special characters and mnemonics during macro execution. However, it prevents resolution of the value

Copyright © 2008, SAS Institute Inc. All rights reserved. Example 1: Unmatched Quotation Mark (‘) The following %LET statement contains a single quotation mark in the macro variable value: %let singleq=O'neill; %put &singleq; When you submit these statements, you do not receive any output because SAS expects a matching closing quotation mark.

Copyright © 2008, SAS Institute Inc. All rights reserved. Solution: Use the %STR Function To solve this problem, include the %STR function around the SINGLEQ macro variable’s value: %let singleq=%str(O%'neill) %put &singleq; Using %STR results in the following output: 3120 %put &singleq; O'neill

Copyright © 2008, SAS Institute Inc. All rights reserved. Example 2: Percent Sign (%) The following %LET statement contains a percent sign in the macro variable value: %let ex=This macro is called %showme; %put ex=&ex; When you submit these statements, SAS cannot resolve the macro invocation and you receive the following warnings: 20 %let ex= This macro is called %showme; WARNING: Apparent invocation of macro SHOWME not resolved. 21 %put ex=&ex; WARNING: Apparent invocation of macro SHOWME not resolved.

Copyright © 2008, SAS Institute Inc. All rights reserved. 23 %let ex=%nrstr(This macro is called %showme); 24 %put ex=&ex; ex=This macro is called %showme Solution: Use the %NRSTR Function To solve this problem, include the %NRSTR function around the SINGLEQ macro variable’s value: %let ex=%nrstr(This macro is called %showme); %put ex=&ex; Using %NRSTR results in the following output:

Copyright © 2008, SAS Institute Inc. All rights reserved. 31 %put WITH NO QUOTING FUNCTION:; WITH NO QUOTING FUNCTION: 32 %test(&x); ERROR: More positional parameters found than defined. Example 3: Commas (,) In the following %LET statement, commas are used as separators between the values A, B, and C : %macro test(value); %put &value; %mend; %let x=a,b,c; %put WITH NO QUOTING FUNCTION:; %test(&x); SAS interprets these commas as additional parameters, and you receive the following error message:

Copyright © 2008, SAS Institute Inc. All rights reserved. 34 %put WITH THE CORRECT QUOTING FUNCTION:; WITH THE CORRECT QUOTING FUNCTION: 35 %test(%bquote(&x)) a,b,c Solution: Use the %BQUOTE Function To solve this problem, mask the commas by using the %BQUOTE execution-time function: %put WITH THE CORRECT QUOTING FUNCTION:; %test(%bquote(&x)); Using %BQUOTE results in the following output:

Copyright © 2008, SAS Institute Inc. All rights reserved. In the following CALL statement, an ampersand is used to replace the word and in the value Beer&Brats : data _null_; call symputx('milwaukee','Beer&Brats'); run; %put NOT quoted:; %put &milwaukee; When you submit these statements, the macro processor interprets the ampersand as an indication that the name following it is a symbolic reference for a macro variable entry. The processor cannot find the entry in the macro symbols table, so you receive the following warning: 5 %put NOT quoted:; NOT quoted: 6 %put &milwaukee; WARNING: Apparent symbolic reference BRATS not resolved. Beer&Brats Example 4: Ampersand (&)

Copyright © 2008, SAS Institute Inc. All rights reserved. 8 %put THIS is quoted:; THIS is quoted: 9 %put %superq(milwaukee); Beer&Brats Solution: Use the %SUPERQ Function To solve this problem, include the %SUPERQ function around the macro variable: %put THIS is quoted:; %put %superq(milwaukee); %SUPERQ prevents the macro processor from attempting to resolve &Brats, and you receive the following output:

Copyright © 2008, SAS Institute Inc. All rights reserved. Q: Output that was generated with the MPRINT system option looks fine, so why are errors generated?

Copyright © 2008, SAS Institute Inc. All rights reserved. Quoting functions, such as the %STR function in the following example, can cause problems with output generated with the MPRINT option: options mprint; %macro test; %let val=aaa; %let test = %str(%'&val%'); data _null_; val = &test; put val=; run; %mend test; %test The output generated is as follows: Note: Line generated by the macro variable “TEST”. 1 ‘aaa’ ERROR : Expecting an arithmetic expression. ERROR : The option or parameter is not recognized and will be ignored.

Copyright © 2008, SAS Institute Inc. All rights reserved. To solve this problem, use the %UNQUOTE function: options mprint; %macro test; %let val = aaa; %let test = %unquote(%str(%'&val%')); OR data _null_; val = %unquote(&test); put val=; run; %mend test; %test This example outputs VAL=‘aaa’, and no error messages are generated. A: %UNQUOTE Function

Copyright © 2008, SAS Institute Inc. All rights reserved. Q: How do you conditionally execute a macro from within a DATA step?

Copyright © 2008, SAS Institute Inc. All rights reserved. A: CALL EXECUTE Routine Use the CALL EXECUTE routine to conditionally execute a macro from within a DATA step, as shown in this example: /* Compile the macro BREAK. The BYVAL */ /* parameter is generated in the CALL */ /* EXECUTE routine. */ %macro break(byval); data age_&byval; set sorted(where=(age=&byval)); run; %mend; proc sort data=sashelp.class out=sorted; by age; run; options mprint; data _null_; set sorted; by age; if first.age then call execute(‘%break(‘||age||’)’); run; (continued)

Copyright © 2008, SAS Institute Inc. All rights reserved. MPRINT(BREAK): data age_11; MPRINT(BREAK): set sorted(where=(age=11)); MPRINT(BREAK): run; MPRINT(BREAK): data age_12; MPRINT(BREAK): set sorted(where=(age=12)); MPRINT(BREAK): run; MPRINT(BREAK): data age_13; MPRINT(BREAK): set sorted(where=(age=13)); MPRINT(BREAK): run; MPRINT(BREAK): data age_14; MPRINT(BREAK): set sorted(where=(age=14)); MPRINT(BREAK): run; MPRINT(BREAK): data age_15; MPRINT(BREAK): set sorted(where=(age=15)); MPRINT(BREAK): run; MPRINT(BREAK): data age_16; MPRINT(BREAK): set sorted(where=(age=16)); MPRINT(BREAK): run; A: CALL EXECUTE Routine Output generated by the previous program:

Copyright © 2008, SAS Institute Inc. All rights reserved. Q: Can I use DATA step variables in a %IF-%THEN statement?

Copyright © 2008, SAS Institute Inc. All rights reserved. A: Data Step Variables Cannot Be Used in %IF- %THEN Statements In the following example, the %IF condition contains the DATA step variable named TEXT: %macro test; data sample; text=“OPEN”; %if TEXT=OPEN %then %do; %put TRUE?; %end; run; %mend; This is a literal comparison, and TEXT=OPEN will never be true.

Copyright © 2008, SAS Institute Inc. All rights reserved.  This statement is the part of the SAS macro language that conditionally generates text.  An expression can only contain operands that are constant text or text expressions that generate text.  This statement cannot refer to DATA step variables.  This statement executes during macro execution. If the statement is contained in a DATA step, it is executed before DATA step compilation.  This statement is the part of the SAS language that conditionally executes SAS statements during DATA step execution.  An expression can only contain operands that are DATA step variables, character or numeric constants, or date and time constants.  This statement executes during DATA step execution. If the statement is contained within a macro, it is stored as text. %IF-%THEN Statement IF-THEN Statement Comparison of %IF-%THEN Statement with IF-THEN statement

Copyright © 2008, SAS Institute Inc. All rights reserved. Recommended Reading Burlew, Michelle SAS Macro Programming Made Easy, Second Edition. Cary, NC: SAS Press. Carpenter, Art Carpenter's Complete Guide to the SAS ® Macro Language, Second Edition. Cary, NC: SAS Press. Tyndall, Russ. Give Your Macro Code an Extreme Makeover: Tips for even the most seasoned macro programmer. Cary, NC: SAS Institute Inc. Available at support.sas.com/techsup/technote/ts739.pdf.

Copyright © 2008, SAS Institute Inc. All rights reserved. Questions?

Copyright © 2008, SAS Institute Inc. All rights reserved.