array2vec {hyperSpec} | R Documentation |
Calculate the vector index from array indices, and vice versa.
array2vec(iarr, dim) vec2array(ivec, dim)
iarr |
vector with the indices into the array dimensions |
ivec |
scalar with the index into the vector |
dim |
vector with the array dimensions, as returned by dim (x) |
array
s are numeric
s with a dim
attribute and are
stored with the first index moving fastest (i.e. by column). They can
be indexed both ways.
array2vec
returns a scalar, vec2array
a matrix
.
C. Beleites
see Extract
on the difference of indexing
an array
with a vector or a matrix
.
arr <- array (rnorm (24), dim = 2 : 4) arr v <- matrix(c(2, 2, 2), nrow = 1) i <- array2vec (v, dim = dim (arr)) i arr[v] arr[i] arr[c(2, 2, 2)] ## indexing with a vector arr[2] i <- 14 v <- vec2array (i, dim = dim (arr)) v arr [v] arr [i]