topic Re: About random number "ranuni" in SAS Programming

About random number "ranuni"

yuwentaiwan — Wed, 16 Dec 2020 08:10:34 GMT

Good afternoon fellow SAS users and the overall SAS community.

I want to random select then nember 1~100.

What is the different

y1=1+99*ranuni(seed);

y2=100*ranuni(seed);

Thank you!!

Re: About random number "ranuni"

ballardw — Wed, 16 Dec 2020 08:18:13 GMT

When you use

1+99*ranuni(seed)

Then the minimum value will be no less than 1.

When you use

100*ranuni(seed);

you may have a minimum like 100* 0.00000001.

I don't know what you mean by "select then nember 1~100" but if your goal is to generate random integers from 1 to 100 then use

rand('integer',100);

Re: About random number "ranuni"

PeterClemmensen — Wed, 16 Dec 2020 08:19:43 GMT

Do you want to simulate a general random number or an integer?

Re: About random number "ranuni"

yuwentaiwan — Wed, 16 Dec 2020 08:20:57 GMT

I want to simulate a general random number,thanks.

Re: About random number "ranuni"

andreas_lds — Wed, 16 Dec 2020 08:25:19 GMT

Try

r = rand('Integer', 1, 100);

Re: About random number "ranuni"

s_lassen — Wed, 16 Dec 2020 08:38:55 GMT

I would use the more advanced random number generator, with the RAND function. RANUNI is relatively primitive - it generates a sequence of 2^32 integers (the seed value), which then repeats, and the integer values are all unique within the sequence. For your actual purpose it may be good enough, but make a habit of using the more advanced function.

There is no SEED parameter in RAND, but you can initialize the random number stream with a call to STREAMINIT, e.g.:

data want;
  call streaminit(253252); /* the seed initialization */
  n1=rand('UNIFORM',1,100); /* corresponds to 1+99*ranuni(seed), values between 1 and 100 */
  n2=rand('UNIFORM',100); /* corresponds to 100*ranuni(seed), values between 0 and 100 */
run;