R/size.R

In matlab2r: Translation Layer from MATLAB to R

#' @title Size of an object
#' @description This functions tries to replicate the behavior of the base
#' function "size" in Matlab
#' @param x object to be evaluated
#' @param d dimension of object to be evaluated
#' @note On MATLAB, size(1, 100) returns 1. As a matter of fact, if the user
#' calls for a dimension which x doesn't have `size()` always returns 1. R's
#' default behavior is more reasonable in those cases (i.e., returning NA),
#' but since the point of this function is to replicate MATLAB behaviors
#' (bugs and questionable behaviors included), this function also does this.
#' @export
#' @return A vector whose size is the number of dimensions of x and whose scale
#' corresponds to the number of elements on (i.e. the size of) each dimension.
#' @examples
#' size(10)
#' size(1:4)
#' size(matrix(1:6, 2))
#' size(array(1:24, c(2, 3, 4)))
#'
size <- function(x, d) {
  # Determining the number of dimensions
  if (all(is.na(x))) {
    if (missing(d)) {
      return(c(0, 0))
    } else {
      return(ifelse(d <= 2, 0, 1))
    }
  }
  if (length(x) == 1) {
    # x is surely a scalar
    return(1)
  } else {
    # x is a vector, a matrix or an array
    n_dim <- ifelse(is.null(dim(x)), 1, length(dim(x)))
    if (missing(d)) {
      if (n_dim == 1) {
        out <- c(1, length(x))
      } else {
        out <- dim(x)
      }
    } else {
      out <- ifelse(n_dim == 1, c(1, length(x))[d], dim(x)[d])
      if (is.na(out)) out <- 1 # for MATLAB compatibility
    }
    return(out)
  }
}