#' Count

#'

#' Count the numbers of observations within groups

#'

#' @param dt_ the data table to uncount

#' @param ... groups

#' @param na.rm should any rows with missingness be removed before the count? Default is \code{FALSE}.

#' @param wt the wt assigned to the counts (same number of rows as the data)

#'

#' @examples

#'

#' library(data.table)

#' dt <- data.table(

#'   x = rnorm(1e5),

#'   y = runif(1e5),

#'   grp = sample(1L:3L, 1e5, replace = TRUE),

#'   wt = runif(1e5, 1, 100)

#'   )

#'

#' dt_count(dt, grp)

#' dt_count(dt, grp, na.rm = TRUE)

#' dt_count(dt, grp, na.rm = TRUE, wt = wt)

#'

#' @import data.table

#' @importFrom stats complete.cases

#'

#' @export

dt_count <- function(dt_, ..., na.rm = FALSE, wt = NULL){

}

#' @export

dt_count.default <- function(dt_, ..., na.rm = FALSE, wt = NULL){

}