[R-gui] runif function

[Charilaos Skiadas]

On Nov 8, 2007, at 12:07 PM, shweta wrote:

> Hi ,
>
> I was trying to generate random data in R using the runif function.  
> But
> I am not sure how do I combine the x and y to get a 2d array/matrix  
> in a
> variable z.
> As seen below I am getting the same numbers in x as 1 and in y as 2.1
> respectively. I would like to get different & random numbers in x & y.
>
> Please let me know.

Looking at ?runif, you can see that the syntax for runif is: runif(n,  
min=0, max=1)

So when you call runif(N,1), what you really call is runif 
(N,min=1,max=1), so you are asking R to generate random numbers  
between 1 and 1. Of course they will all be equal to 1. Try runif(N),  
or specify both a min and a max.

PS: Not sure what this has to do with GUI though, isn't that more  
appropriate to R-help instead of r-sig-gui?

> x <- array(runif(N,1),dim=c(N,1))
>> x
>      [,1]
> [1,]    1
> [2,]    1
> [3,]    1
> [4,]    1
> [5,]    1
> [6,]    1
> [7,]    1
> [8,]    1
> [9,]    1
> [10,]    1
>> y <- array(2*x + runif(N,1)/10)
>> y
> [1] 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1
>
> Thanks & Regards,
> Shweta.

Haris Skiadas
Department of Mathematics and Computer Science
Hanover College