R/add_data.R

In pollyvote/pollyvoter: Aggregate Components, Calculate Forecasts and Determine Errors for Election Results.

#' add data (to a pollyvote object)
#' 
#' Adds data, so far only implemented for pollyvote objects.
#'
#' @param pv [\code{pollyvote}]\cr
#'   the pollyvote object to add the data to.
#' @param newdata [\code{data.frame}]\cr
#'   the data to add to the pollyvote object.
#'   should contain this columns: id, date, source, party, percent
#' @param ... additional arguments giving information about \code{newdata}.
#' 
#' @examples
#' data("polls_individual")
#' pv = add_data(pv, newdata = polls_individual, country = "D", 
#'               region = "national", source_type = "poll", election = "BTW")
#' 
#' @return The pollyvote object with added data.
#'
#' @export
add_data = function(pv, newdata = data.frame(), ...) {
  UseMethod("add_data")
}

#' add data to a pollyvote object
#' 
#' Adds data to a pollyvote opbject.
#'
#' @inheritParams add_data
#' @importFrom plyr rbind.fill
#' 
#' @examples
#' data("polls_individual")
#' pv = add_data(pv, newdata = polls_individual, country = "D", 
#'               region = "national", source_type = "poll", election = "BTW")
#' 
#' @return The pollyvote object with added data.
#'
#' @export
add_data.pollyvote = function(pv, newdata = data.frame(),
                              ...) {
  # input checking
  assert_class(pv, "pollyvote")
  assert_data_frame(newdata)
  
  # run check on additional arguments
  check_additional_args(newdata, pv, ...)
  
  # add additional arguments to newdata
  args = list(...)
  newdata[,names(args)] = args
  
  # run checks on the data
  newdata = check_data(newdata, pv)

  # add data to pv
  # TODO maybe better with join/merge, in case the same data is added twice
  pv$data = plyr::rbind.fill(pv$data, newdata)
  
  return(pv)
}


#' checks additional arguments to add_data function
#' 
#' internal check function if additional arguments to pollyvoter::add_data are 
#' permissible for a pollyvote object
#'
#' @inheritParams add_data
#' @param ... additional named arguments to be checked.
#' 
#' @examples
#' pv = create_pollyvote(perm_countries = "D")
#' data("polls_individual")
#' check_additional_args(polls_individual, pv)
#' 
#' @return Nothing. Only throws error message if arguments are not feasible.
#'
check_additional_args = function(newdata, pv, ...) {
  args = list(...)
  # check arg names with pv
  for(i in names(args)) {
    if(!(i %in% pv$perm_colnames)) {
      stop(paste0(i, " is not a permissible colum name for newdata.",
                  " It must be one of c('", 
                  paste0(pv$perm_colnames, collapse = "', '"), "')"))
    }
  }
  
  # check arg names with data
  for(i in names(args)) {
    if(i %in% colnames(newdata)) {
      warning(paste0(i, " is already a colum name in newdata."))
    }
  }
  
  # check length of additional arguments
  lapply(args, function(arg) {
    if(length(arg) != 1 | length(arg) == nrow(newdata)) {
      stop(paste("Argument", names(arg), " has to be of length 1 or ncol(newdata)."))
    }
  })
  return(NULL)
}