R help - Jun 2011 - Qs on "vector of lists", etc.

I'm pretty new to R, so please forgive the cluelessness of these questions.

Is it true that it is not possible to have a "vector or lists" in R?

Is a "list of lists" the closest one can get to a "vector of
lists"?

Is it possible to have a "matrix of lists" in R?  Or an "array of
lists"?

Thanks!

Roy

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On 01.06.2011 18:59, Roy Shimizu wrote:
> I'm pretty new to R, so please forgive the cluelessness of these
questions.
>
> Is it true that it is not possible to have a "vector or lists" in
R?
>
> Is a "list of lists" the closest one can get to a "vector of
lists"?
Actually a list is a vector of mode "list".

Hence if you have a list of lists, it *is* a vector of lists and behaves 
consistantly (e.g. when subsetiing with [] rather than [[]]).

L <- list(list(a=1, b=2), list(c=3, d=4))

L[1] # L can be considered a vector of mode list.


> Is it possible to have a "matrix of lists" in R?  Or an
"array of lists"?
Yes:

  X <- matrix(L, nrow=2)
  X[1,1]
  X[2,1]

or even:

  dim(X) <- c(1,2,1)
  mode(X)  # "list"
  class(X) # "array"

Uwe Ligges



> Thanks!
>
> Roy
>
> 	[[alternative HTML version deleted]]
>
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