[R] 4D data acsess

[David Winsemius]

On Jun 29, 2011, at 4:56 PM, katarv wrote:

> Hi Sarah,
>
> I use readMat function, from R.matlab function.
>
> str(X) tells that
>
> X : num [1:64, 1:64, 1:21, 1:300]  as I said, the first 3 columns  
> are x,y,z
> coordinates. And I need all values in the last column correcponding  
> to a
> given (x,y,z) coordinate.

You should be able to access those values with:

X[1,1,1, ]

or equivalently:

X[1,1,1,1:300]

>
> if you list the values of X,

> then they are non zero, but for some reason R
> tells that dim(X): NULL

Now that seems a bit odd. What happens if you try:

Y <- X
dim(Y) <- c(64,64,21,300)
Y[ 1, 1, 1, ]

>
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>
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David Winsemius, MD
West Hartford, CT