topic Re: variables combination in SAS Procedures

variables combination

Fred_Gavin — Wed, 24 Aug 2011 02:01:47 GMT

Dear All,

I want to write a code to check every possible combination of variables for their values.

For example:

A B C D E F G ........

Yes Yes No Yes

No No Yes Yes

.......................................

For 7 variables with 2 selections, there are 21 combinations.

How can I write a code that if any two of A B C ..... G..... with "Yes", then the newvariable: new1 = "Yes", ie. A=Yes, D= Yes then new1 = "Yes". if A=No, D=Yes, then new1 = "No". ?

Thanks and Regards

Fred

variables combination

Doc_Duke — Wed, 24 Aug 2011 02:13:55 GMT

This is a case where binary (0/1) coding for no and yes make the task incredibly easy.

IF sum(of a--g)=2 then new1=1; ELSE new1=0;

This says if exactly 2 are yes, then set new1 to 1.

So you could recode a-g in an array and apply the logic above. Otherwise, you could write a DO loop to accomplish the same thing; something like

ARRAY vars a--g;

CountYes=0;

DO i=1 to DIM(vars);

IF vars{i}='Yes' THEN CountYes+1;

END;

IF CountYes=2 THEN new1='Yes'; ELSE new1='No';

Doc Muhlbaier

Duke

Re: variables combination

MikeZdeb — Wed, 24 Aug 2011 02:34:29 GMT

Hi ... here's another idea, works no matter how many answers you have ...

data x;

input (answer1-answer4) (: $3.);

datalines;

Yes Yes No Yes

No No Yes Yes

No No No No

Yes Yes No No

Yes Yes Yes Yes

No Yes No No

;

run;

data x;

set x;

new = ifc(countc(catt(of answer:),'Y') ge 2, 'YES' , 'NO');

run;

proc print data=x noobs;

run;

answer1 answer2 answer3 answer4 new

Yes Yes No Yes YES

No No Yes Yes YES

No No No No NO

Yes Yes No No YES

Yes Yes Yes Yes YES

No Yes No No NO

fyi ... "Searching for Variable Values with CAT Functions: An Alternative to Arrays and Loops"

http://www.nesug.org/Proceedings/nesug09/ff/ff04.pdf

Re: variables combination

Ksharp — Wed, 24 Aug 2011 06:36:08 GMT

Mike.

There is a problem. "catt(of answer:)" is limited by $200. ,so if OP has lots of variables ,you can not hold them all.

SO I think Doc@Duck 's method is good.

Ksharp

Re: variables combination

art297 — Wed, 24 Aug 2011 12:38:47 GMT

Ksharp,

Not so! According to the documentation:

Length of Returned Variable: Special Cases

The CATT function returns a value to a variable, or returns a value in a temporary buffer. The value that is returned from the CATT function has the following length:

up to 200 characters in WHERE clauses and in PROC SQL
up to 32767 characters in the DATA step except in WHERE clauses
up to 65534 characters when CATT is called from the macro processor

Re: variables combination

MikeZdeb — Wed, 24 Aug 2011 12:55:12 GMT

Hi ... original posting mentioned 7 variables, plus as Art said ... the limit is the max length of a

character variable, 32K+.

Re: variables combination

Ksharp — Thu, 25 Aug 2011 03:55:39 GMT

Learned it. Art.T

I should check the documentation firstly before commenting something.

But I still insist that Doc@Duck 's code is better and more robust. Excuse me.

Regards!

Ksharp