Hi,
As an exercise, I am trying to create a list of 10 random number vectors in a
loop. I can create the vectors but am unsure how to assemble them in the list as
part of the loop. Any advice?
# Number of vectors to create
n <- c(1:10)
# Create empty list to store vectors
list_of_vecs <- list()
# Create n vectors of random numbers - length 10. This works ok.
for (i in seq_along(n)){
? assign(paste('vec_', i, sep = ''), rnorm(10,0,1))
}
# But how do I append them in a list. This doesn?t work:
for (i in seq_along(n)){
? list_of_vecs <- list(list_of_vecs,(assign(paste('vec_', i, sep =
''), rnorm(10,0,1))))
}
Thank you,
Paul
[[alternative HTML version deleted]]
Hi Paul,
The easy to understand way is:
n <- c(1:10)
# Create empty list to store vectors
list_of_vecs <- list()
# Create n vectors of random numbers - length 10. This works ok.
for (i in n){
list_of_vecs[[i]]<-rnorm(10,0,1)
}
If you really want to use "assign":
for (i in n){
vecname<-paste('vec_', i, sep = '')
assign(vecname, rnorm(10,0,1))
list_of_vecs[[i]]<-get(vecname)
}
Jim
On Tue, Dec 6, 2016 at 8:44 PM, Paul Sanfilippo <prseye at gmail.com>
wrote:> Hi,
>
> As an exercise, I am trying to create a list of 10 random number vectors in
a loop. I can create the vectors but am unsure how to assemble them in the list
as part of the loop. Any advice?
>
>
> # Number of vectors to create
> n <- c(1:10)
>
> # Create empty list to store vectors
> list_of_vecs <- list()
>
> # Create n vectors of random numbers - length 10. This works ok.
> for (i in seq_along(n)){
> assign(paste('vec_', i, sep = ''), rnorm(10,0,1))
> }
>
> # But how do I append them in a list. This doesn?t work:
> for (i in seq_along(n)){
> list_of_vecs <- list(list_of_vecs,(assign(paste('vec_', i, sep
= ''), rnorm(10,0,1))))
> }
>
>
> Thank you,
>
> Paul
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
Thank you Jim.
On 6 December 2016 at 9:17:21 pm, Jim Lemon (drjimlemon at gmail.com) wrote:
Hi Paul,
The easy to understand way is:
n <- c(1:10)
# Create empty list to store vectors
list_of_vecs <- list()
# Create n vectors of random numbers - length 10. This works ok.
for (i in n){
list_of_vecs[[i]]<-rnorm(10,0,1)
}
If you really want to use "assign":
for (i in n){
vecname<-paste('vec_', i, sep = '')
assign(vecname, rnorm(10,0,1))
list_of_vecs[[i]]<-get(vecname)
}
Jim
On Tue, Dec 6, 2016 at 8:44 PM, Paul Sanfilippo <prseye at gmail.com>
wrote: > Hi,
>
> As an exercise, I am trying to create a list of 10 random number vectors in
a loop. I can create the vectors but am unsure how to assemble them in the list
as part of the loop. Any advice?
>
>
> # Number of vectors to create
> n <- c(1:10)
>
> # Create empty list to store vectors
> list_of_vecs <- list()
>
> # Create n vectors of random numbers - length 10. This works ok.
> for (i in seq_along(n)){
> assign(paste('vec_', i, sep = ''), rnorm(10,0,1))
> }
>
> # But how do I append them in a list. This doesn?t work:
> for (i in seq_along(n)){
> list_of_vecs <- list(list_of_vecs,(assign(paste('vec_', i, sep =
''), rnorm(10,0,1))))
> }
>
>
> Thank you,
>
> Paul
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
[[alternative HTML version deleted]]
On 06 Dec 2016, at 11:17 , Jim Lemon <drjimlemon at gmail.com> wrote:> Hi Paul, > The easy to understand way is: > > n <- c(1:10) > # Create empty list to store vectors > list_of_vecs <- list() > > # Create n vectors of random numbers - length 10. This works ok. > for (i in n){ > list_of_vecs[[i]]<-rnorm(10,0,1) > }As a principle, you want list_of_vecs <- vector("list", 10) to avoid extending the list on each iteration. However, a simpler way is replicate(10, rnorm(10), simplify=FALSE) (where the simplify bit prevents conversion to 10x10 matrix) or lapply(1:10, function(i) rnorm(10)) -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com