[R] Error in apply(x2, 1, diff) : dim(X) must have a positive length

[R. Michael Weylandt]

What package is the bootstrap() function from? There are many
functions by that name....

My hunch is that it takes a vector at a time and puts it through
dif.mns so that leads to the error in the apply() call but I can't
verify.

Michael

On Mon, Feb 13, 2012 at 10:34 AM, hithit168 <ccchristy at live.com> wrote:
> Thank you for your help, David. I was trying to run bootrapping on the
> dataset "shoes" from MASS package. But I still have some problem here.
>
>> as.matrix(data.frame(shoes),nrows=10,ncols=2,byrow=T)
> A B
> [1,] 13.2 14.0
> [2,] 8.2 8.8
> [3,] 10.9 11.2
> [4,] 14.3 14.2
> [5,] 10.7 11.8
> [6,] 6.6 6.4
> [7,] 9.5 9.8
> [8,] 10.8 11.3
> [9,] 8.8 9.3
> [10,] 13.3 13.6
>> y=as.matrix(data.frame(shoes),nrows=10,ncols=2,byrow=T)
>> class(y)
> [1] "matrix"
>> apply(y,1,diff)
> [1] 0.8 0.6 0.3 -0.1 1.1 -0.2 0.3 0.5 0.5 0.3
>> dif.mns <- function(x2,tr1=.1,tr2=.2){
> + diffs=apply(x2,1,diff)
> + mn1=mean(diffs)
> + mn2=mean(diffs,tr=.1)
> + mn3=mean(diffs,tr=.2)
> + mn4=median(diffs)
> + mns=c(mn1,mn2,mn3,mn4)
> + list(mnds=round(mns,3))}
>> dif.mns(y,tr1=.1,tr2=.2)
> $mnds
> [1] 0.410 0.400 0.417 0.400
>
>> bootstrap(y,nboot=1000,theta=dif.mns)
> Error in apply(x2, 1, diff) : dim(X) must have a positive length
>
> I am not sure what I am doing wrong. When I run apply(y,1,diff) I am able to
> get output, and when I run dif.mns with just the original dataset, I am also
> able to get output.
>
>
>
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