[R] data.frame bug?

[Thomas Lumley]

On Fri, 18 Oct 2002, Patrick Connolly wrote:

> On Thu, 17-Oct-2002 at 04:30PM -0500, Chong Gu wrote:
>
> |>
> |> I'd like to create a data frame with components
> |>
> |> > jk$x1
> |> [1] 2
> |> > jk$x2
> |>          [,1] [,2]
> |> [1,]    0    0
> |>
> |> I used to be able to do it with
> |>
> |> > jk <- data.frame(x1=2,x2=I(matrix(0,1,2)))
> |>
> |> But now I get a error message.
> |>
> |> Can I still do what I want?  Thanks for any help.
>
> Not if you want to call and use it a data frame.  A list as you've
> made could still suit your purposes, but if you want a dataframe, it
> has to have elements that are of equal lengths.
>

This is slightly misleading.  It's quite possible to have complicated
objects in a data frame, including things that are in fact matrices
eg
   data.frame(a=1:2,b=Surv(1:2))
where the second column is a matrix with some extra attributes. This is a
Good Thing.

It has in the past been possible to have matrices in data frames, and it
still is possible to create them -- the reported bug is in printing them,
and I think it is a bug.

	-thomas



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