What is R's multidimensional equivalent of rbind and cbind?
See the abind package. If you want them to bind on a 3rd dimension, do this:
library(abind)
abind(x, y, along = 3)
See ?abind
Also, abind gives a lot more convenience, but for simple binding you can just manipulate the values directly, based on the default ordering:
array(c(x, y), dim = c(2, 2, 2))