[R] appending an R-object to a list

[Uwe Ligges]

On 06.04.2010 23:28, David.Epstein wrote:
>
> How do I append an R-object to a list?
> I want to start with an empty list, and append R-objects one by one.
> Does this start with a command like
> mylist<- NULL
> ??
>
> I have read a few answers on R-help to questions like this, but they all
> seem to be well off the point. Sometimes it's assumed that the list is a
> vector---not my case.
> One answer I read said that the object appended must be a list. This doesn't
> make sense to me. I don't want a list of lists. I want a list of R-objects.
>
> I tried using c(with.stuff.inside.the.brackets). This seemed to unwrap my
> structures, storing the individual components rather than the R-objects
> themselves.
>
> I tried looking in "Intro to R" but could find nothing relevant.
>
> Thanks for any help.
> David
>
>


Well lists are vectors of mode list.

If you have a list L and want to append an element l, you can simply add 
it by:

c(L, list(l))

One element of a List L extracted by vector indexing (single brackets):
L[1]
will show you got a list of length one back (since L is a vector of mode 
list).

You may want to play around and find that things are even simpler than 
you thought they are.


Uwe Ligges