topic Re: Substring and input finctions in a Macro in SAS Programming

Substring and input finctions in a Macro

jacksonan123 — Wed, 30 Jan 2019 14:31:03 GMT

I have the following data set which is being processed within a macro:

id time ipred occ sid
subj1 0 0
subj1 0.5 0
subj1 1 0
subj1 2 0
subj1 3 0
subj1 4 0
subj1 5 0

I would like to:

1.take a substring of the variable subj1 to have a result of 1. How can this be done when the substring is a value within the id column?

2.I tried to convert id from a character to numeric value using sid=input(id,8.) but a s you can see it is converted but the column entries are missing. What am I doing wrong to cause the column entries to be missing?

I have included my code which is part of a Macro.

 
/*16)**************TEST CONCENTRATIONS************************/
data simt&i._&j; 
retain  _name_ cln lagn ka1n ka2n vfn fn ;
set nall_final&i._&j;
if Treat in ('ATES') ;
if _n_=2;
do time=0, 0.5,1,2,3,4,5,6,7,8,9,10,12,14,16,18,20,24;
/*DOSE IS IN NG AND CP IN NG/ML*/
dose=40000;  
 
	
cln=input (cl,8.);
rename cln=cl;
lagn= input (lag,8.);
rename lagn= lag;
ka1n=input (ka1,8.);
rename ka1n=ka1; 
ka2n=input (ka2,8.);
rename ka2n=ka2;
vfn=input (vf,8.);
rename vfn=vf;
fn=input (logit,8.);
rename fn=f; 
id=input(_name_,8.);
rename _name_=id;
drop id cl lag ka1 ka2 vf logit;
substr(subj1&i,1,4);
sid=input (id,8.);

output ;
	   end;

run;

Re: Substring and input finctions in a Macro

Kurt_Bremser — Wed, 30 Jan 2019 14:51:53 GMT

PLEASE do always post example data in a working data step with datalines; right now it's very hard to make sense of your data:

id time ipred occ sid
subj1 0 0
subj1 0.5 0
subj1 1 0
subj1 2 0
subj1 3 0
subj1 4 0
subj1 5 0

as you seem to have 5 variables, but the last two of them are always missing?

This statement

substr(subj1&i,1,4);

will throw a syntax error. substr() must either be a part of an expression (right side of an assignment, or in a condition), or be used on the left side of an assignment, but you don't have one here. Since your variable is already called subj1, the resolution of macro variable &i (which I take to be a counter of a %do loop) will result in a variable you do not have on your dataset.

Start out with a piece of working Base SAS code before you wrap it into a macro definition.

Re: Substring and input finctions in a Macro

Astounding — Wed, 30 Jan 2019 14:52:27 GMT

As you have seen, the INPUT function can't read "subj" as numeric. If you want to get just the digits, use COMPRESS:

id2 = compress(id, , 'kd');

KD means keep only the digits.

That value can be converted to numeric:

id3 = input(id2, 8.);

And you could combine these into one statement:

id3 = input(compress(id, , 'kd'), 8.);

Re: Substring and input finctions in a Macro

jacksonan123 — Wed, 30 Jan 2019 17:52:12 GMT

Please see the reply I received from Astounding (Esteemed Advisor) which I
will post and answered my question with code that is operates inside the
Macro.

Re: Substring and input finctions in a Macro

jacksonan123 — Wed, 30 Jan 2019 17:54:35 GMT

Your code worked perfectly.

I had a follow-up question. Is there a reason that my original code using substr didn't work?

Re: Substring and input finctions in a Macro

Astounding — Wed, 30 Jan 2019 19:01:35 GMT

Presumably, you are talking about this:

substr(subj1&i, 1, 4)

Macro language resolves first, and SAS sees the result only. For example, when &i is 1, SAS sees:

substr(subj11, 1, 4)

This causes SAS to look for a variable named subj11 (which I presume doesn't exist).