[R] match lists

[Gabor Grothendieck]

Try this:

A <- list(matrix(c(2,3,3,1,2,2), 3, dimnames = list(NULL, letters[1:2])),
          matrix(c(3,3,2,5,1,3), 3, dimnames = list(NULL, letters[3:4])))

B <- list(matrix(c(1:5, 20*(1:5), 10+20*(1:5)), 5,
             dimnames = list(NULL, letters[5:7])),
          matrix(c(1:5, 10*(1:5), 10+10*(1:5)), 5,
             dimnames = list(NULL, letters[8:10])))

lapply(1:2, function(i) lapply(1:2, function(j) B[[i]][A[[i]][,j],]))



On 10/29/06, Heymans, MW <mw.heymans at vumc.nl> wrote:
> Dear list,
>
> I have this problem, please your advice.
>
> I have list A that contains two matrix elements:
> [[1]]
>     a b
> [1,] 2 1
> [2,] 3 2
> [3,] 3 2
> [[2]]
>     c d
> [1,] 3 5
> [2,] 3 1
> [3,] 2 3
>
> and list B, that also contains 2 matrices:
> [[1]]
>     e   f   g
> [1,] 1  20  30
> [2,] 2  40  50
> [3,] 3  60  70
> [4,] 4  80  90
> [5,] 5 100 110
> [[2]]
>     h  i  j
> [1,] 1 10 20
> [2,] 2 20 30
> [3,] 3 30 40
> [4,] 4 40 50
> [5,] 5 50 60
>
> Now I want to match each column of list A with each row of list B in such a way that element 1 of list A corresponds to element 1 of list B (and element 2 of A with 2 of B).
> So, in total there will be 4 new matrices, 1 for each column of list A. For example, for column a of list A the new matrix will be:
>
> 2  40  50
> 3  60  70
> 3  60  70
>
> thanks,
> Martijn
> VUmc
> Amsterdam
>
>
>        [[alternative HTML version deleted]]
>
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