How do I smartly subset an array in R with dynamic dimensions? -

i'm crafting simulation model, , think problem has easy fix, i'm not used working arrays. let's have array, array1, has 3 dimensions. first 2 of constant , equal length, l, third dimension can of length 1 x @ given time.

i want able periodically subset array1 create second array, array2, composed of up to last y "sheets" of array1. in other words, if length of third dimension of array1 greater y, want last y sheets of array1 but, if it's less y, want sheets of array1.

i know can crudely pull off using tail function , little finagling:

tmp1 = tail(array1, (l*l*y)) array2 = array(tmp1, dim = (l, l, (l*l/length(tmp1)))) 

but seems there more elegant way of doing this. there equivalent of tail arrays in r? or there way array2 produced via simple logical indexing of array1? or perhaps apply function used somehow?

were after this?

a <- array(1:(3*4*5), dim=c(3,4,5)) x <- dim(a)[3] y <- 2 a[, , seq(to=x, len=min(x, y))]  , , 1       [,1] [,2] [,3] [,4] [1,]   37   40   43   46 [2,]   38   41   44   47 [3,]   39   42   45   48  , , 2       [,1] [,2] [,3] [,4] [1,]   49   52   55   58 [2,]   50   53   56   59 [3,]   51   54   57   60