topic Re: Can't use macro variable in proc CAS in SAS Programming

Can't use macro variable in proc CAS

Ullsokk — Tue, 15 Sep 2020 08:20:39 GMT

I am trying to check if the dataset is already loaded to cas using this code:

%let data= 'MyDataSet';

proc cas;
    table.tableExists result =r / name="&data" caslib="MyCasLib";
	print(r);
    if r=0  then do;
		print("table is not loaded");
		%let loaded = 0;
    end;
    else ;
		print("Table already loaded");
quit;

The code works if I hard code the table name, but not if I try to use a macro value, and enter "MyDataSet" in stead. From the log, I can see that the macro variable is not resolved when I try to use the macro variable &data

Re: Can't use macro variable in proc CAS

Kurt_Bremser — Tue, 15 Sep 2020 08:28:21 GMT

Everything after the %LET up to the semicolon (except leading and trailing blanks) is stored in the macro variable, so your statement resolves to

table.tableExists result =r / name="'MyDataSet'" caslib="MyCasLib";

which is not correct syntax. Always keep in mind that the macro processor is a text generating/replacing engine, and you do not need quotes around strings, unless you explicitly want them later (which is usually not the case).

Re: Can't use macro variable in proc CAS

Kurt_Bremser — Tue, 15 Sep 2020 08:37:06 GMT

And your next mistake is this

%let loaded = 0;

Macro statements are resolved while the code is fetched for interpretation/compilation, so this statement is resolved before PROC CAS runs, and &loaded will be zero in all cases.

You have to use the CASL functions SYMPUT or SYMPUTX to conditionally set a macro variable.

Re: Can't use macro variable in proc CAS

Ullsokk — Tue, 15 Sep 2020 09:46:51 GMT

Thansks, I did not know about cas spesific symput statements and %let beeing resolved beforehand. Got it working using the casl symput