Re-sort list of vectors

You could try using one of the sparse representations of matrices in the
SparseM or Matrix packages.  Both packages have vignettes.

Andy

From: Jan Hummel

 Thanks a lot! But unfortunately I will not know the
dimensions of both lists. And further, the lists may be
(partly) disjoint as: x <- list("1"=c(a=1, b=2, c=3),
"2"=c(d=4, b=5, e=6)). And last but not least I'm really have
to have access to the names of the named list items.

The problem I dealt with is in unlist() merging the names
together, as you can see in your example given: "V1", "V2"
and "V3". Because off interpreting the names later as
identifiers in db queries I'm really interested in getting
something like list("a"=c("1"=1), "b"=c("1"=2, "2"=5),
"c"=c("1"=3), "d"=c("1"=4), "e"=c("1"=6)) for the above input.
By giving the result this way I'm able to extract both names
from two sets as well as the according value between both items.

One point could be to build a matrix but this matrix would
have many NA's. So I prefer Lists of Lists.

Any ideas?

cheers
      Jan

-----Urspr??ngliche Nachricht-----
Von: Liaw, Andy [mailto:andy_liaw at merck.com]
Gesendet: Montag, 15. August 2005 17:31
An: Jan Hummel; r-help at stat.math.ethz.ch
Betreff: RE: [R] Re-sort list of vectors

If all vectors in the list have the same length, why not use
a matrix?  Then you'd just transpose the matrix if you need
to.  If you really have to have it as a list, here's one possibility:

x <- list("1"=c(a=1, b=2, c=3), "2"=c(a=4, b=5, c=6)) x

$"1"
a b c
1 2 3

$"2"
a b c
4 5 6

as.list(as.data.frame(t(matrix(unlist(x), nrow=3))))

$V1
[1] 1 4

$V2
[1] 2 5

$V3
[1] 3 6

Andy

From: Jan Hummel

Hi.
Can anyone suggest a simple way to re-sort in R a list of

vectors of

the following form?

input
$"1"
    a       b       c
    1       2       3
$"2"
    a       b       c
    4       5       6

Output should be something like:
"a"
    "1" 1
    "2" 4
"b"
    "1" 2
    "2" 5
"c"
    "1" 3
    "2" 6

I've been futzing with mapply(), outer(), split(), rbind()

and so on

but haven't found an elegant solution.

Thanks,
Jan.

P.S. E-mailed CCs of posted replies appreciated.