topic Re: Inserting a datastep variable value within another variable name in SAS Programming

Inserting a datastep variable value within another variable name

spirto — Sat, 09 Apr 2016 15:32:24 GMT

Hello, I have a simple problem I would apprecieate any help with.

Suppose in my dataset I have a variable called TYPE which is A, B, C, or D. Furthermore I have four additional variable xA, xB, xC, xD. What I would like to do is create a new variable x that has the appropriate xA, xB, etc value depending on the TYPE. So if TYPE=A then x=xA, etc. Here is an example table;

TYPE	xA	xB	xC	xD	x
A	1	3	0	2	1
D	0	9	5	3	3
C	4	2	0	0	0

I've tried x=x||TYPE and call execute('x=x'||TYPE||';'); but to no avail. I read that you can use some combination of symput and symget.

At worst I can do if TYPE='A' then x=XA, etc. but this is really inefficent code (I have 20 different TYPE letters).

Is there an elegant solution for this?

Thank you!

Re: Inserting a datastep variable value within another variable name

Reeza — Sat, 09 Apr 2016 15:44:52 GMT

VVALUEX function is what you're after. It returns it as a character though, so you need to convert it to numeric, if required.

x=vvaluex("x"|Type);

data want;
input type $ xA xB xC xD;
x=vvaluex("x"||type);
cards;
A 1 3 0 2
D 0 9 5 3
C 4 2 0 0 
;
run;

Re: Inserting a datastep variable value within another variable name

jklaverstijn — Sat, 09 Apr 2016 15:46:18 GMT

This seems like an excellent oppportunity to use arrays. Image to arrays, one temporary with 'A', 'B', etc. The other one with XA, XB, ...

The loop up the index of TYPE in the first and use that index to assign the value of X to the variable in the second array with the found index.

data want;
    array types[4] $ _temporary_  ('A' 'B' 'C' 'D');
    array xs[*] xa xb xc xd;
    type='D';
    x=100;
    do i=1 to dim(types);
      if type=types[i] then xs[i]=x;
    end;
    put _all_;
run;

Hope this gets you on your way,

- Jan

Re: Inserting a datastep variable value within another variable name

jklaverstijn — Sat, 09 Apr 2016 15:47:44 GMT

Oh rats. I did it the other way round. Looks like @Reeza has the proper solution.

- Jan.