Dear list members,
I need to create a table from a huge list object,
this list consists of matrices of the same size (but with different
content).
The resulting n tables should contain the same rows from all matrices.
For example:
n <- 23
x <- array(1:20, dim=c(n,6))
huge.list <- list()
for (i in 1:1000) {
huge.list[[i]] <- x }
# One of 1000 matrices
huge.list[[1]][1:4, 1:6]
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 4 7 10 13 16
[2,] 2 5 8 11 14 17
[3,] 3 6 9 12 15 18
[4,] 4 7 10 13 16 19
...
# The result should be like that:
# One of n tables (with the row 4 from all 1000 matrices):
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 4 7 10 13 16 19
[2,] 4 7 10 13 16 19
[3,] 4 7 10 13 16 19
[4,] 4 7 10 13 16 19
...
[999,] 4 7 10 13 16 19
[1000,] 4 7 10 13 16 19
# I tried to convert a list object to an array
ARR <- array(unlist(huge.list), dim = c(dim(huge.list[[1]]),
length(huge.list)))
# then split it and use abind function, but it didn't work
Thanks in advance!
Vladimir
--
Vladimir Mikryukov
PhD student
Institute of Plant & Animal Ecology UD RAS,
Lab. of Population and Community Ecotoxicology
[8 Marta 202, 620144, Ekaterinburg, Russia]
Tel. +7 343 210 38 58 (ext.290)
Fax: +7 343 260 82 56, +7 343 260 65 00
[[alternative HTML version deleted]]
try something like this:
n <- 23
x <- array(1:20, dim = c(n, 6))
huge.list <- rep(list(x), 1000)
out <- lapply(1:4, function (i) {
t(sapply(huge.list, "[", i = i, j = 1:6))
})
out[[1]]
out[[4]]
I hope it helps.
Best,
Dimitris
On 8/24/2010 11:29 AM, Vladimir Mikryukov wrote:> Dear list members,
>
> I need to create a table from a huge list object,
> this list consists of matrices of the same size (but with different
> content).
>
> The resulting n tables should contain the same rows from all matrices.
>
> For example:
> n<- 23
> x<- array(1:20, dim=c(n,6))
>
> huge.list<- list()
> for (i in 1:1000) {
> huge.list[[i]]<- x }
>
>
> # One of 1000 matrices
> huge.list[[1]][1:4, 1:6]
> [,1] [,2] [,3] [,4] [,5] [,6]
> [1,] 1 4 7 10 13 16
> [2,] 2 5 8 11 14 17
> [3,] 3 6 9 12 15 18
> [4,] 4 7 10 13 16 19
> ...
>
> # The result should be like that:
> # One of n tables (with the row 4 from all 1000 matrices):
> [,1] [,2] [,3] [,4] [,5] [,6]
> [1,] 4 7 10 13 16 19
> [2,] 4 7 10 13 16 19
> [3,] 4 7 10 13 16 19
> [4,] 4 7 10 13 16 19
> ...
> [999,] 4 7 10 13 16 19
> [1000,] 4 7 10 13 16 19
>
>
> # I tried to convert a list object to an array
> ARR<- array(unlist(huge.list), dim = c(dim(huge.list[[1]]),
> length(huge.list)))
> # then split it and use abind function, but it didn't work
>
> Thanks in advance!
> Vladimir
>
> --
> Vladimir Mikryukov
> PhD student
> Institute of Plant& Animal Ecology UD RAS,
> Lab. of Population and Community Ecotoxicology
> [8 Marta 202, 620144, Ekaterinburg, Russia]
> Tel. +7 343 210 38 58 (ext.290)
> Fax: +7 343 260 82 56, +7 343 260 65 00
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
On Aug 24, 2010, at 11:29 AM, Vladimir Mikryukov wrote:> Dear list members, > > I need to create a table from a huge list object, > this list consists of matrices of the same size (but with different > content). > > The resulting n tables should contain the same rows from all matrices. > > For example: > n <- 23 > x <- array(1:20, dim=c(n,6)) > > huge.list <- list() > for (i in 1:1000) { > huge.list[[i]] <- x } > > > # One of 1000 matrices > huge.list[[1]][1:4, 1:6] > [,1] [,2] [,3] [,4] [,5] [,6] > [1,] 1 4 7 10 13 16 > [2,] 2 5 8 11 14 17 > [3,] 3 6 9 12 15 18 > [4,] 4 7 10 13 16 19 > ... > > # The result should be like that: > # One of n tables (with the row 4 from all 1000 matrices): > [,1] [,2] [,3] [,4] [,5] [,6] > [1,] 4 7 10 13 16 19 > [2,] 4 7 10 13 16 19 > [3,] 4 7 10 13 16 19 > [4,] 4 7 10 13 16 19 > ... > [999,] 4 7 10 13 16 19 > [1000,] 4 7 10 13 16 19 > > > # I tried to convert a list object to an array > ARR <- array(unlist(huge.list), dim = c(dim(huge.list[[1]]), > length(huge.list))) > # then split it and use abind function, but it didn't workYou need to look in the direction of lapply() & friends do.call(rbind,lapply(huge.list,"[",4,)) t(sapply(huge.list,"[",4,TRUE)) both seem to cut the mustard. (Notice that sapply() will cbind() the results automagically, and that for some odd reason it is more unhappy about missing arguments than lapply is.) For more intelligible and generalizable code, also consider do.call(rbind, lapply(huge.list, function(x)x[4,])) -- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com