[R] Simulation

[Wacek Kusnierczyk]

Barry Rowlingson wrote:
> On Wed, May 13, 2009 at 4:26 PM, Gábor Csárdi <csardi at rmki.kfki.hu> wrote:
>   
>> On Wed, May 13, 2009 at 5:13 PM, Debbie Zhang <debbie0621 at hotmail.com> wrote:
>>     
>>> Dear R users,
>>>
>>> Can anyone please tell me how to generate a large number of samples in R, given certain distribution and size.
>>>
>>> For example, if I want to generate 1000 samples of size n=100, with a N(0,1) distribution, how should I proceed?
>>>
>>> (Since I dont want to do "rnorm(100,0,1)" in R for 1000 times)
>>>       
>> Why not? It took 0.05 seconds on my 5 years old laptop.
>>     
>
>  Second-guessing the user, I think she maybe doesn't want to type in
> 'rnorm(100,0,1)' 1000 times...
>
>  Soln - "for" loop:
>
>  > z=list()
>  > for(i in 1:1000){z[[i]]=rnorm(100,0,1)}
>
> now inspect the individual bits:
>
>  > hist(z[[1]])
>  > hist(z[[545]])
>
> If that's the problem, then I suggest she reads an introduction to R...

i'd suggest reading the r inferno by pat burns [1], where he deals with
this sort of for-looping lists the way it deserves ;)

vQ

[1] http://www.burns-stat.com/pages/Tutor/R_inferno.pdf