%str() understanding

[David_Billa]

May I know the meaning of %str( ) in below %do loop and %let statement?

  /* Drop unwanted fields from the tables */
   %let l_i=1;
   PROC SQL NOPRINT;
   %do %until(%scan(&l_freqDs,&l_i, %str( )) EQ );
      %let l_dsName =%scan(&l_freqDs,&l_i, %str( ));
      %let l_varName= %scan(&l_tables,&l_i, %str( ));
      ALTER TABLE &l_dsName  DROP &l_varName;
      %let l_i=%eval(&l_i + 1);
   %end;
   QUIT;

[Kurt_Bremser]

Since the macro language strips blanks from values, you must use the %STR macro function to feed a blank to the SCAN.

[David_Billa]

@Kurt_Bremser Won't the SCAN function consider blank as default delimiter without we being explicitly adding %str()?

[Astounding]

Yes, blanks are included as default delimeters. However, periods are also included (and would appear in any list of data sets that includes permanently saved data sets). So the code ensures that blanks are delimiters but periods are not.