topic Re: Evaluating a macro variable string that contains variable names in SAS Programming

Evaluating a macro variable string that contains variable names

HoaTruong — Sat, 04 Mar 2017 22:21:29 GMT

Hi,

I would be very grateful if someone could please help me with the following query. I have a macro variable that contains a string, but the expression contains variable names. In the example below, the macro variable contains an expression that refers to variables 'a' and 'b'. The dataset 'testdata' contains these variables. I would like to know how to set 'c' to be the numeric result of evaluating the macro variable 'test', so should equal 3.

%Let test = "a+b";

Data testdata;

a=1;

b=2;

c=???;

Run;

Many thanks,

Hoa

Re: Evaluating a macro variable string that contains variable names

Reeza — Sat, 04 Mar 2017 23:00:55 GMT

Remove quotes from the %let statement.

Replace ??? In datastep with &c.

At its basics consider macro variables as a Find/Replace algorithm. The result needs to be valid SAS code.

Re: Evaluating a macro variable string that contains variable names

avinashns — Sun, 05 Mar 2017 02:26:57 GMT

%Let test = a+b;

Data testdata;
	a=1;
	b=2;
	c=&test.;
Run;

Re: Evaluating a macro variable string that contains variable names

HoaTruong — Sun, 05 Mar 2017 17:58:20 GMT

Thank you very much! I forgot I had the quotes in the macro expression - too much staring at code..! 😃