topic Re: Using a text to call a macro variable (dynamic) in SAS Programming

Using a text to call a macro variable (dynamic)

Thiago_Oliv — Fri, 16 Apr 2021 15:00:13 GMT

Hi!

I need some help to create a dynamic variable, is something like that:

%let var1 = 5;

%let var2 = 3;

So, i need to call the var1, but i want to make it more dynamic to help in my program i tried this:

%let version = 1

%put &'var'&version

-> ERROR

%put &var&version

-> ERROR 'VAR' doesn't exist

to call var1, but i didn't get success, i tried to use eval too, bu no success 😞

Re: Using a text to call a macro variable (dynamic)

ballardw — Fri, 16 Apr 2021 15:13:12 GMT

Please show what you expect for output.

& references a macro variable. &var1 for example. Quotes are not valid as part of a macro variable name which is the complaint from &'var

%put &var1.&version;

There is a complicated concept called indirect referencing which may be another option

%let var1 = 5;

%let var2 = 3;
%let version = 1;

%put &&var&version.;

When multiple && are encountered the SAS, in effect "holds" on of the & and resolves part of the rest so var&version becomes Var1 and then the &var1 is implemented.

But if you don't know enough of the macro language to understand why &'var' was a bad idea you are very likely not ready for this as as resolving such takes a lot of practice. (and often locked up SAS sessions from bad results. Save code often.)

Re: Using a text to call a macro variable (dynamic)

Tom — Fri, 16 Apr 2021 15:16:44 GMT

To reference a macro variable prefix the name with the & character. In the %PUT statement you can also &= prefix to have it print the name and the value.

%let var1 = 5;
%let var2 = 3;
%put Value of VAR1 is &var1;
%put &=var1;

A macro variable name cannot include quotes so this cannot work.

%put &'var'&version;

If you want the macro processer to reevaluate the text it generates for more macro triggers use a double &.

%let var1=WANT;
%let version=1;
%put &&ver&version;

It will replace the double & with a single & and then make another pass over the resulting string.

&&var&version -->  &var1 --> WANT

Re: Using a text to call a macro variable (dynamic)

Reeza — Fri, 16 Apr 2021 15:27:13 GMT

%PUT &&&var&version;