A character operand was found in the %EVAL function or %IF condition - sas

Question

/* Here is the code that is having an issue*/
%macro numstats(var = ,file=, format=);
%let dsid=open(&file.,i);
%if %LENGTH(&var.) > 8 AND %VARTYPE(&dsid.,%VARNUM(&dsid.,&var.))='N' %then %do;
Proc SQL;
SQL code
quit;
end;
%mend numstats;
I am having the following error when running this code: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required.
I have played with this code extensively to try different online solutions and cannot figure out why I am still receiving this issue. Please help!
Side Note: The reason I had to add this IF statement is to try to find out whether the variable was a date variable. All my date variables are Date9. so if it is Numeric and has a length greater than 8, then I want to add date formatting that I would not add to regular numeric variables. If anyone can think of an easier way to do that, then i am open to that as well, but please help me figure out this error!

Answer 1

If you want to call data step functions within macro code then you need to call them with the %SYSFUNC() macro function. Here is an example of a macro function that will do that for you.
%macro varinfo
/*----------------------------------------------------------------------
Retrieve attribute of a specified variable.
----------------------------------------------------------------------*/
(ds /* Data set name */
,var /* Variable name */
,info /* information attribute to return - Default is NUM */
);
/*----------------------------------------------------------------------
Example values for INFO parameter:
NUM = variable number
LEN = length of variable
FMT = format of variable
INFMT = informat of variable
LABEL = label of variable
TYPE = type of variable (N for numeric, C for character)
------------------------------------------------------------------------
Usage Examples:
%if %varinfo(&data,NAME)
%then %put input data set contains variable NAME;
%put Variable &column in &data has type %varinfo(&data,&column,type);
------------------------------------------------------------------------
Notes:
The macro call resolves to 0 when either the data set does not exist
or the variable is not in the specified data set.
Invalid values for the INFO parameter generate a SAS ERROR message.
----------------------------------------------------------------------*/
%local dsid rc varnum;
%let dsid = %sysfunc(open(&ds));
%if (&dsid) %then %do;
%let varnum = %sysfunc(varnum(&dsid,&var));
%if (&varnum) & %length(&info) %then
%sysfunc(var&info(&dsid,&varnum))
;
%else
&varnum
;
%let rc = %sysfunc(close(&dsid));
%end;
%else 0;
%mend varinfo;
Using this your macro might become something like this:
%macro numstats(var = ,file=, format=);
%if %varinfo(&file,&var,type)=N and
DATE = %sysfunc(substrn(%varinfo(&file,&var,fmt),1,4))
%then %do;
* do something ;
%end;
%mend numstats;