topic Length of a variable created by a PROC FCMP character function in SAS Programming

Length of a variable created by a PROC FCMP character function

SR_FR — Thu, 14 Mar 2019 12:15:23 GMT

Hi,

When you use for instance the SUBSTR function to create a new variable, the length of that new variable is equal to the length of the variable you use as an argument.

I created a character function with PROC FCMP and I'd like my function to have the same property.

If my function statement is like this :

function extrait(chaine $,dlm $,pos) $ ;

The length of the variable created when I use this function is 33 (BTW, why?). I can give an arbitrary large value for the length of the created variables (say 500...) but this would be a waste of resources.

I'd like that length to be equal to the length of the variable I'll use as the "chaine" argument.

is this possible?

best regards

Sébastien

Re: Length of a variable created by a PROC FCMP character function

ballardw — Thu, 14 Mar 2019 16:50:35 GMT

@SR_FR wrote:

Hi,

When you use for instance the SUBSTR function to create a new variable, the length of that new variable is equal to the length of the variable you use as an argument.

I created a character function with PROC FCMP and I'd like my function to have the same property.

If my function statement is like this :
function extrait(chaine $,dlm $,pos) $ ;
The length of the variable created when I use this function is 33 (BTW, why?). I can give an arbitrary large value for the length of the created variables (say 500...) but this would be a waste of resources.

I'd like that length to be equal to the length of the variable I'll use as the "chaine" argument.

is this possible?

best regards

Sébastien

Likely the reason your test variable has length of 33 is the first returned value had that length. The basic rule for non-defined lengths of character variables is the first use will set the length.

The easiest I could see if you don't want to be bothered to assign an explicit length to a "new" variable is to do something such as call to substr or similar function prior to the function call:

dummy = substr(var,1);

dummy = extrait(var, ',',3) ; (or however you want to call your function.

Re: Length of a variable created by a PROC FCMP character function

SR_FR — Fri, 15 Mar 2019 08:35:49 GMT

the solution your propose does the job !

thanks!

about the 33, well, it's still a mystery...

The first returned value can not help to understand this length since the length of a character variable is decided during the compilation of the program.

may be the complete program would help to solve the mystery...

proc fcmp outlib=sasuser.funcs.temp;
   function extrait(chaine $,dlm $,pos) $ ;
   temp=0;
      do i=1 to pos;
         temp=find(chaine,dlm,temp+1);
      end;
   return(substr(chaine,1,temp-1));
   endsub;
run;

options cmplib=sasuser.funcs;

data toto;
   x="azz,bs,cezz,dd,e";
   y=3;
   dlm=',';
   gogo=extrait(x,dlm,y);
run;

Sébastien