topic Re: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required in SAS Data Science

A character operand was found in the %EVAL function or %IF condition where a numeric operand is required

eagles_dare13 — Wed, 31 Dec 2014 20:24:28 GMT

I have this code inside a macro:

%if &macro_var =%str() %then

%do;

%put ERROR: The macro_var is not set.;

%return;

%end;

I am getting error:

WARNING: Apparent symbolic reference macro_var not resolved.

ERROR: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required. The condition was: &macro_var=

The WARNING is ok..because the macro_var has not been set. But Why is it throwing an error? Why is it looking for a numeric operand? How to resolve this? Basically I am trying to check if a macro variable is null or has been set with a proper value.

Re: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required

art297 — Wed, 31 Dec 2014 20:41:14 GMT

You have to show more of your code (e.g., the entire macro and how you call it). Your code appears to work fine if used as below:

%macro test(macro_var);

%if &macro_var =%str() %then

%do;

%put ERROR: The macro_var is not set.;

%return;

%end;

%else %do;

%put macro_var was set.;

%return;

%end;

%mend test;

%test(PD_OVERRIDE_FILENAME)

%test( )

Re: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required

eagles_dare13 — Wed, 31 Dec 2014 21:14:28 GMT

Thank you. You can replicate the error like this:

%macro test();

%if &macro_var =%str() %then

%do;

%put ERROR: The macro_var is not set.;

%return;

%end;

%else %do;

%put macro_var was set.;

%return;

%end;

%mend test;

%test();

Re: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required

Tom — Wed, 31 Dec 2014 21:24:17 GMT

Since the macro variable doesn't exist (see the first warning message) it is attempting to evaluate the expression &macro_var=. It is interpreting the & as the AND operator and so generates the error since you cannot use AND with a text string (macro_var). For example if you wrote %put %eval( 1 & 2) it would not generate an error message since the arguments for the & operator are both numeric.

You could add %IF %SYMEXIST(macro_var) %THEN to make sure the variable is defined.

You could add some quotes so that the implied %EVAL() in the %IF statement knows that you are comparing strings. %if "&macro_var"="" %then ...

Re: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required

art297 — Wed, 31 Dec 2014 21:27:59 GMT

My suggestion is the same as Tom's. You actually have 3 conditions to test. E.g.:

%macro test();

%if %symexist(macro_var) %then %do;

%if &macro_var =%str() %then %do;

%put ERROR: The macro_var is set but null.;

%return;

%end;

%else %do;

%put macro_var was set.;

%return;

%end;

%else %do;

%put ERROR: The macro_var is not set.;

%return;

%end;

%mend test;

%test();

%let macro_var=PD_OVERRIDE_FILENAME;

%test();

%let macro_var=;

%test();