[R] indexing an array

Agustin Lobo
Thu, 20 Sep 2001 12:05:37 -0000

Is not

lambda[rep(1:N,rep(3,N),state[rep(1:N,rep(3,N)],] ?

(i.e., for N=5 , the first index is:
> rep(1:5,rep(3,5))
 [1] 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5

but make sure that state[rep(1:N,rep(3,N)] is within 1:M.

Agus

Dr. Agustin Lobo
Instituto de Ciencias de la Tierra (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona SPAIN
tel 34 93409 5410
fax 34 93411 0012
alobo at ija.csic.es


On Thu, 20 Sep 2001 siim at obs.ee wrote:

> Dear everybody,
>
> I have a following problem.  I have a 3D array
>
> lambda <- array( dim=c(N,M,M-1))
>
> where I have to extract the elements as follows:
>
> lambda[ 1, state[1], 1]
> lambda[ 1, state[1], 2]
> ...
> lambda[ 1, state[1], M-1]
> lambda[ 2, state[2], 1]
> ...
> lambda[ 2, state[2], M-1]
> ...
> lambda[ N, state[N], M-1]
>
> i.e. the result should be a 2D array, where the second index follows the
> first one and the third is free (lambda[i,state[i],]).  The process is
> to be repeated so I do not want to write a cycle.
>
> Any suggestions?
>
> Thanks in advance,
>
> Ott Toomet
>
>
>
>
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