R/datatable.R

In raubreywhite/RAWmisc: R Convenience functions

#' Recoding variables in data.table
#'
#' @param d a
#' @param switch a vector coded like: c("old"="new")
#' @param var a
#' @param oldOnLeft a
#' @import data.table
#' @export RecodeDT
RecodeDT <- function(d, switch, var, oldOnLeft = TRUE) {
  if (oldOnLeft) {
    oldNames <- names(switch)
    newNames <- switch
  } else {
    oldNames <- switch
    newNames <- names(switch)
  }
  if (is.numeric(d[[var]])) {
    switch <- data.table::data.table(orig = as.numeric(oldNames), replace = as.numeric(newNames))
  } else {
    switch <- data.table::data.table(orig = oldNames, replace = newNames)
  }

  txt <- sprintf("d[switch, on=.(%s=orig), %s:=replace]", var, var)
  eval(parse(text = txt))
}