R/data_usps.R

In Rdimtools: Dimension Reduction and Estimation Methods

#' Load USPS handwritten digits data
#'
#' The well-known USPS handwritten digits from "0" to "9". Though the original version
#' of each digit is given as a \eqn{16\times 16} matrix of grayscale image, it is
#' convention to vectorize it. For each digit, 1100 examples are given.
#'
#' @usage data(usps)
#'
#' @examples
#' \donttest{
#' # load the data
#' data(usps)
#'
#' # visualize
#' opar <- par(no.readonly=TRUE, mfrow=c(1,3), pty="s")
#' image(t(matrix(usps$data[4400,],nrow=16)[16:1,])) # last of digit 4
#' image(t(matrix(usps$data[9900,],nrow=16)[16:1,])) # last of digit 9
#' image(t(matrix(usps$data[6600,],nrow=16)[16:1,])) # last of digit 6
#' par(opar)
#' }
#'
#' @format a named list containing\describe{
#' \item{data}{an \eqn{(11000\times 256)} matrix where each row is a number.}
#' \item{label}{(factor) a length-\eqn{11000} class label in \eqn{0,1,\ldots,9}.}
#' }
#'
#'
#' @concept data
"usps"