topic Re: DO loops and Array processing in SAS Programming

DO loops and Array processing

KDang — Wed, 01 Dec 2010 14:31:25 GMT

Hi,

I have values for the following variables that are either 0 or 1 :
q1a_1 - q1a_14
q1b_1 - q1b_14
q1c_1 - q1c_14
q1d_1 - q1d_14

There are a few new variables I want to create:

q1before_1 - q1before_14: for each iteration 1 - 14, this variable will check if q1a_{i} OR q1c_{i} contains a 1 (or sum of GE 1), if GE 1 then q1before_{i} = 1 .

q1after_1 - q1after_14: for each iteration 1 - 14, this variable will check if q1b_{i} OR q1d_{i} contains a 1 (or sum of GE 1), if GE 1 then q1after_{i} = 1 .

I can write out each iteration, but I'm looking for a solution (if possible) that will condense my code with DO loops and arrays (or other solutions).

Thanks for your help!

Re: DO loops and Array processing

SPR — Wed, 01 Dec 2010 14:57:30 GMT

Hello KDang,

Is this the code are you looking for?
[pre]
data a;
array q1a {14} q1a_1-q1a_14;
array q1b {14} q1b_1-q1b_14;
array q1c {14} q1c_1-q1c_14;
array q1d {14} q1d_1-q1d_14;
array q1before {14} q1before_1-q1before_14;
array q1after {14} q1after_1- q1after_14;
/* Array Initialization */;
do i=1 to 14;
q1a[i]=RAND('BERNOULLI',0.1);
q1b[i]=RAND('BERNOULLI',0.2);
q1c[i]=RAND('BERNOULLI',0.3);
q1d[i]=RAND('BERNOULLI',0.4);
end;
/* Calculation */;
do i=1 to 14;
if q1a[i]+q1c[i] GE 1 then q1before[i]=1;
if q1b[i]+q1d[i] GE 1 then q1after[i]=1;
end;
drop i;
run;
[/pre]
Sincerely,
SPR

Re: DO loops and Array processing

Peter_C — Wed, 01 Dec 2010 15:14:31 GMT

> q1before_1 - q1before_14: for each iteration 1 - 14,
> this variable will check if q1a_{i} OR q1c_{i}
> contains a 1 (or sum of GE 1), if GE 1 then
> q1before_{i} = 1 .

BEFORE = (ASET or CSET);

> q1after_1 - q1after_14: for each iteration 1 - 14,
> this variable will check if q1b_{i} OR q1d_{i}
> contains a 1 (or sum of GE 1), if GE 1 then
> q1after_{i} = 1 .

AFTER = ( BSET or DSET);

the SAS code could be as simple if you use the (less-well-documented) array style called IMPLICIT arrays[pre]
array aset q1a_1 - q1a_14 ;
array bset q1b_1 - q1b_14 ;
array cset q1c_1 - q1c_14 ;
array dset q1d_1 - q1d_14 ;
array before q1before_1 - q1before_14 ;
array after q1after_1 - q1after_14 ;

do over before ;
AFTER = (BSET or DSET);
BEFORE = (ASET or CSET);
end ;[/pre]
For those who prefer nothing remotely undocumented or like to see more syntax, I reccommend the exercise of providing the demonstration..
;-)
peterC

Re: DO loops and Array processing

KDang — Wed, 01 Dec 2010 15:22:13 GMT

Yes thank you SPR, it worked perfectly.

Although, I didnt include the array initialization step, just because I dont really understand it..
i'm just curious what it does?

Re: DO loops and Array processing

KDang — Wed, 01 Dec 2010 15:32:52 GMT

Thanks PeterC that worked perfectly as well, really simple and easy to understand.

Re: DO loops and Array processing

SPR — Wed, 01 Dec 2010 17:40:57 GMT

Hello KDang,

The Initialization step has been included to create initial data for your input arrays a1q, etc. It is not necessary in your program.

Sincerely,
SPR