[R] How to fix indeces in a loop

[Francesca]

Thanks a lot!
Francesca

On 18 May 2012 18:21, arun <smartpink111 at yahoo.com> wrote:
> Hi Francesca,
>
>> for(i in 1:length(x1<-c(100,1000,10000))){
>  j<-x1[i]
>  x1[i]<-mean(j)
>  }
>
>> x1
> [1]   100  1000 10000
>
>
>
> A.K.
>
>
>
> ----- Original Message -----
> From: Francesca <francesca.pancotto at gmail.com>
> To: r-help at r-project.org
> Cc:
> Sent: Friday, May 18, 2012 10:59 AM
> Subject: [R] How to fix indeces in a loop
>
> Dear Contributors,
> I have an easy question for you which is puzzling me instead.
> I am running loops similar to the following:
>
>
> for (i in c(100,1000,10000)){
>
> print((mean(i)))
> #var<-var(rnorm(i,0,1))
> }
>
> This is what I obtain:
>
> [1] 100
> [1] 1000
> [1] 10000
>
> In this case I ask the software to print out the result, but I would
> like to store it in an object.
> I have tried a second loop, because if I index the out put variable
> with the i , i get thousands of records which I do not want(a matrix
> of dimension 10000).
>
> for (i in c(100,1000,10000)){
> for (j in 1:3){
> x[j]<-((mean(i)))
> #var<-var(rnorm(i,0,1))
> }}
>
> This is the x:
>
>       [,1] [,2] [,3]
> [1,] 10000   NA   NA
> [2,] 10000   NA   NA
> [3,] 10000   NA   NA
>
> Clearly the object x is storing only the last value of i, 10000.
>
> I would like to save a vector of dimension 3 with content 100,1000,10000,
> but I do not know how to fix the index in an efficient manner.
>
> Thanks for any help you can provide.
> Francesca
>
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>



-- 

Francesca

----------------------------------
Francesca Pancotto, PhD
Università di Modena e Reggio Emilia
Viale A. Allegri, 9
40121 Reggio Emilia
Office: +39 0522 523264
Web: http://www2.dse.unibo.it/francesca.pancotto/