R/vec2tab.R

In dkahle/latter: Interface to 'LattE' and '4ti2'

#' Vector to array conversion
#'
#' Convert a vector into an array given a set of dimensions; it therefore simply
#' wraps [aperm()] and [array()].
#'
#' This function converts an array (or a multi-way contingency table) into a
#' vector, using a consistent ordering of the cells. The ordering of the cells
#' is lexicographic and cannot be specified by the user.
#'
#' @param vec A vector
#' @param dim The desired array dimensions, oftentimes a vector of the number of
#'   levels of each variable in order
#' @return An array
#' @export
#' @seealso [tab2vec()], [aperm()], [array()]
#' @examples
#'
#' data(Titanic)
#' str( Titanic )
#' str( tab2vec(Titanic) )
#' 
#' # convert it back into a table (names are removed)
#' vec2tab(
#'   tab2vec(Titanic), 
#'   dim(Titanic)
#' )
#' 
#' # check that they are the same
#' all( vec2tab(tab2vec(Titanic), dim(Titanic)) == Titanic )
#'
#' 
vec2tab <- function(vec, dim){
  aperm(
    array(vec, rev(dim)),
    length(dim):1
  )
}