[R] Question on list objects

[Charles C. Berry]

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