topic Re: Generate two-dimensional array with random binomial data in SAS Programming

Generate two-dimensional array with random binomial data

Dinurik — Thu, 13 Jun 2019 16:23:55 GMT

Dear SAS Programmers,

How do I generate an array and fill it with random binomial data?

Say, I need an array with 100 rows and 5 columns, and I want the probability to be equal in all columns, say p=0.1.

My current code (sorry, if it's totally stupid) is:

data Table (keep=aids);
call streaminit(4321);
array p[5] _temporary_ (repeat(0.1, 5));
do i = 1 to 500;
aids = rand("Table", of p[*]);
output;
end; end;
run;

First of all, the repeat function in the array does not work (because it probably shouldn't be there). But when I replace it with (0.1, 0.1, 0.1, 0.1, 0.1) the code produces a single variable with 500 entries instead of arranging the results in an array.

Thank you!

Re: Generate two-dimensional array with random binomial data

Reeza — Thu, 13 Jun 2019 16:29:59 GMT

data want;

array col(5);

do nrows=1 to 100;

    do i=1 to dim(col);

           col(i) = rand('binomial', 0.1);

      end;

     output;

end;

run;

Depends a bit on what you mean by

I want the probability to be equal in all columns, say p=0.1.

Random usually means that you won't have equal distributions, but the probability should be 0.1 across all observations anyways, dependent on sample size of course.

@Dinurik wrote:

Dear SAS Programmers,

How do I generate an array and fill it with random binomial data?

Say, I need an array with 100 rows and 5 columns, and I want the probability to be equal in all columns, say p=0.1.

My current code (sorry, if it's totally stupid) is:

data Table (keep=aids);
call streaminit(4321);
array p[5] _temporary_ (repeat(0.1, 5));
do i = 1 to 500;
aids = rand("Table", of p[*]);
output;
end; end;
run;

First of all, the repeat function in the array does not work (because it probably shouldn't be there). But when I replace it with (0.1, 0.1, 0.1, 0.1, 0.1) the code produces a single variable with 500 entries instead of arranging the results in an array.

Thank you!

Re: Generate two-dimensional array with random binomial data

Dinurik — Thu, 13 Jun 2019 16:48:59 GMT

Hi Reeza,

Thanks a lot. I tried:

data want;
call streaminit(4321);
array col(5);
do nrows=1 to 100;
do i=1 to dim(col);
col(i) = rand('Bernoulli', 0.1);
end;
output;
end;
run;

And it worked.

Is there any resource/article, that you could refer me to so I can teach myself on this topic?

Re: Generate two-dimensional array with random binomial data

Reeza — Thu, 13 Jun 2019 16:53:30 GMT

Simulating data or just generate data step logic?

For simulating data, Rick Wicklins blog and book are the best references:

https://www.amazon.ca/Simulating-Data-SAS-Rick-Wicklin/dp/1612903320

@Dinurik wrote:

Is there any resource/article, that you could refer me to so I can teach myself on this topic?

Re: Generate two-dimensional array with random binomial data

Dinurik — Thu, 13 Jun 2019 17:13:00 GMT

Thanks so much!

What about data step logic? Data step completely throws me off, so I would really appreciate any recommendation of what to read =).

Re: Generate two-dimensional array with random binomial data

Reeza — Thu, 13 Jun 2019 17:24:12 GMT

@novinosrin may have better suggestions. I'm an older user (before StackOverflow, FB or Twitter) so learned via reading the documentation.

Which I would actually highly recommend.

https://documentation.sas.com/?docsetId=lrcon&docsetTarget=n1lw46l098rlqsn1948oua32fnsl.htm&docsetVersion=9.4&locale=en

Re: Generate two-dimensional array with random binomial data

Dinurik — Fri, 14 Jun 2019 14:50:48 GMT

Wonderful, thanks!