R/mutate_dt.R

In hope-data-science/tidydt: Tidy Verbs for 'data.table'

#' @title Mutate columns in data.frame
#' @description Analogous function for \code{mutate} and \code{transmute} in \pkg{dplyr}.
#' @param data data.frame
#' @param ... List of variables or name-value pairs of summary/modifications
#'   functions.
#' @return data.table
#' @seealso \code{\link[dplyr]{mutate}}
#' @examples
#'
#' iris %>% mutate_dt(one = 1,Sepal.Length = Sepal.Length + 1)
#' iris %>% transmute_dt(one = 1,Sepal.Length = Sepal.Length + 1)
#'
#' @rdname mutate
#' @export

mutate_dt = function(data,...){
  dt = as_dt(data)
  substitute(list(...)) %>%
    deparse() %>%
    str_c(collapse = "") %>%
    #str_squish() %>%
    str_extract("\\(.+\\)")-> dot_string
  eval(parse(text = str_glue("dt[,`:=`{dot_string}][]")))
}

#' @rdname mutate
#' @export
transmute_dt = function(data,...){
  dt = as_dt(data)
  dt = as_dt(data)
  substitute(list(...)) %>%
    deparse() %>%
    str_c(collapse = "") %>%
    str_squish() %>%
    str_extract("\\(.+\\)")-> dot_string
  eval(parse(text = str_glue("dt[,.{dot_string},]")))
}