.BG
.FN dim
.TL
dim: Dimensionality of Vector or Array
.CS
dim(x)
.PP
.AG x
vector or array.
.RT
If `x' is an array, the `Dim' vector of `x'.
If `x' is a vector, a vector of length 1 containing `len(x)'.
If `x' is NULL, `dim(x)' is 0 (since NULL is treated as
a zero-length vector by the `c' function, for example).
.EX
dim(iris)   # returns c(50,4,3)

dim(1:100)   # returns 100

len(dim(y))	# dimensionality of z

if(dim(z)) { ... z ... }  # do not operate on NULL data
.KW array*
.KW basic*
.WR
