[R] Question on list objects
Charles C. Berry
cberry at tajo.ucsd.edu
Sat Jan 8 18:56:20 CET 2011
On Sat, 8 Jan 2011, Ron Michael wrote:
> Hi, I have 2 questions on list object:
>
> 1. Suppose I have a matrix like:
> dat <- matrix(1:9,3)
>
> Now I want to replicate this entire matrix 3 times and put entire result in a list object. Means, if "res" is the resulting list then I should have:
>
> res[[1]]=dat, res[[2]]=dat, res[[3]]=dat
>
> How can I do that in the easilest manner?
See
?rep
...
Examples
...
## replicate a list
...
>
> 2. Suppose I have 2 list objects:
> list1 <- list2 <- vector("list", length=2)
> for(i in 1:2) {
> list1[[i]] <- matrix(rnorm(15), 3)
> list2[[i]] <- matrix(rnorm(15), 3)
> }
>
> How can I add these 2 list objects? I have tried with just list1+list2, however it is generating some error.
>
See
?mapply
take note of the SIMPLIFY arg, which you want as FALSE
HTH,
Chuck
> Would be grateful for any help.
>
> Thanks,
>
>
> [[alternative HTML version deleted]]
>
>
Charles C. Berry Dept of Family/Preventive Medicine
cberry at tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
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