R/empty.R

In hyperSpec: Work with Hyperspectral Data, i.e. Spectra + Meta Information (Spatial, Time, Concentration, ...)

##' Empty hyperSpec object
##' 
##' Empty produces an hyperSpec object with the same columns and wavelengths as \code{x}.  The new
##' object will either contain no rows at all (default), or the given number of rows with all data
##' initialized to \code{spc} and \code{extra}, respectively.
##' 
##' @aliases empty
##' @author C. Beleites
##' @keywords manip
##' @export
##' @examples 
##' empty (chondro, nrow = 2, spc = 0)
##' @param x hyperSpec object
##' @param nrow number of rows the new object should have
##' @param spc value to initialize the new spectra matrix with
##' @param extra value to initialize the new extra data with
empty <- function (x, nrow = 0, spc = NA, extra = NA) {

  if (nrow (x@data) == 0 && nrow > 0)
    stop ("Empty is not implemented for empty (0 row) objects")

  x@data <- x@data [rep (1L, nrow), ]

  if (nrow > 0){
    x@data$spc [TRUE] <- spc
    x@data[, ! grepl ("^spc$", colnames (x@data))] <- extra
  }

  x
}