[R] apply for list or list -> array

[Roger Bivand]

On Mon, 18 Sep 2006, Ahn ChaeHyung wrote:

> Dear all,
> 
> I have the following list, "aa", composed of two 3*3 tables.  I would like 
> to use "apply" function to summarize it, but "apply" cannot handle "list".  
> I want to do it without using any interation.
> 
> 1. Is there any function like "apply" for list?

?lapply, ?sapply

> 2. Is there any way to transform that "list" to a 2*3*3 "array"?
> 

Among other possibilities:

library(abind)
aa <- list(m1=matrix(rnorm(9), 3, 3), m2=matrix(runif(9), 3, 3))
a1 <- abind(aa, along=3)
str(a1)
dim(a1)


> thanks
> 
> cahn
> 
> -----------------------------------------
> >aa
> [[1]]
>      [,1] [,2] [,3]
> [1,]    1    3    1
> [2,]    2    0    1
> [3,]    1    1    0
> 
> [[2]]
>      [,1] [,2] [,3]
> [1,]    1    3    1
> [2,]    2    0    1
> [3,]    1    1    0
> 
> 
> I would like to avoid any iteration
> 
> 
> 
> -------------------------------------------------
> Ahn, Chaehyung (cahn) Ph.D.
> Alpha-Gamma Technologies Inc.
> My Home: http://blog.naver.com/cahn88
> 
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> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no