On Dec 9, 2009, at 12:14 PM, Peng Yu wrote:
On Tue, Dec 8, 2009 at 11:05 PM, David Winsemius <dwinsem...@comcast.net
> wrote:
On Dec 8, 2009, at 11:37 PM, Peng Yu wrote:
I want to split a matrix, where both 'u' and 'w' are results of
possible ways. However, whenever 'n' changes, the argument passed to
mapply() has to change. Is there a way to pass elements of a list as
multiple arguments?
You need to explain what you want in more detail. In your example
mapply did
exactly what you told it to. No errors. Three matrices. What were you
expecting when you gave it three lists in each argument?
I want a general solution so that I don't have to always write
"v[[1]], v[[2]], ..., v[[n]]" like in the following, because the
following way would not work if 'n' is an arbitrary number.
w=mapply(function(x,y) {cbind(x,y)}, v[[1]], v[[2]], ..., v[[n]])
One way that I can think of is to somehow expand a list (i.e., v in
this case) to a set of arguments that can be passed to 'mapply()'.
The functions illustrated on the help page for Reduce address the task
of passing arbitrarily long lists of arguments to functions expecting
two. It's possible that do.call might address this, but I have not
come up with a strategy that deals with your structures.
--
David.
m=10
n=2
k=3
set.seed(0)
x=replicate(n,rnorm(m))
f=sample(1:k, size=m, replace=T)
u=split(as.data.frame(x),f)
v=lapply(
1:dim(x)[[2]]
, function(i) {
split(x[,i],f)
}
)
w=mapply(
function(x,y) {
cbind(x,y)
}
, v[[1]], v[[2]]
)
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@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.
