topic Re: How to check if the list is empty in SAS Programming

How to check if the list is empty

makset — Mon, 07 Mar 2022 15:35:17 GMT

Hello.
I have the following problem with sas list:

%let List =;
%let N_List = %sysfunc(countw(&List));

533 %let List =;
534 %let N_List = %sysfunc(countw(&List));
ERROR: The function COUNTW referenced by the %SYSFUNC or %QSYSFUNC macro function has too few
arguments

%if &list =  %then %do;
..
%end;

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

How to check if the list is empty???

Thank you very much for all your help

Re: How to check if the list is empty

yabwon — Mon, 07 Mar 2022 11:21:03 GMT

%if %superq(list) = %then %do; ... %end;

Re: How to check if the list is empty

PeterClemmensen — Mon, 07 Mar 2022 11:22:48 GMT

Use a proper macro quoting function or make sure that the &list macro variable is available in the local symbol table for your macro (i.e. create it inside the macro def).

Re: How to check if the list is empty

Tom — Mon, 07 Mar 2022 15:45:28 GMT

If you give %SYSFUNC() at least two arguments then it will not cause the COUNTW() function to issue that error.

937   %let List =;
938   %let N_List = %sysfunc(countw(&List,));
939   %put &=n_list;
N_LIST=0

But you really should be telling COUNTW() what delimiters to use. For example a space.

%let N_List = %sysfunc(countw(&List,%str( )));

Otherwise it uses multiple characters.

the default delimiters depend on whether your computer uses ASCII or EBCDIC characters.

If your computer uses ASCII characters, then the default delimiters are as follows:

blank ! $ % & ( ) * + , - . / ; < ^ |

In ASCII environments that do not contain the ^ character, the SCAN function uses the ~ character instead.

If your computer uses EBCDIC characters, then the default delimiters are as follows:

blank ! $ % & ( ) * + , - . / ; < ¬ | ¢

To simply test if the sting is empty I normally just test for non-zero length.

%if %length(&list) %then ...