

   AArrrraayy EExxtteennttss

        dim(x)
        dim(x) <- values

   VVaalluuee::

        This function retrieves the vector of extents of the
        array given as its argument.  The second form above is
        used to shape a vector as an array by specifying its
        extents.

   SSeeee AAllssoo::

        `ncol', `nrow' and `dimnames'.

   EExxaammpplleess::

        # simple versions of nrow and ncol could be defined as follows
        nrow0 <- function(x) dim(x)[1]
        ncol0 <- function(x) dim(x)[2]

