R/qbs.R

In xhaz: Excess Hazard Modelling Considering Inappropriate Mortality Rates

#' @title qbs function
#'
#' @description a function indicating which covariates have a time-dependent
#' effect in the formula.
#'
#' @param x a covariate to be considered in the \code{xhaz} formula with a
#'  time-dependant effect. Quadratic B-splines with two interior knots are used.
#'
#' @return No return value, called for side effects.
#'
#' @keywords qbs
#'
#' @examples
#'
#' \donttest{
#'
#' library("xhaz")
#' library("numDeriv")
#' library("survexp.fr")
#' library("splines")
#'
#' fit.tdphBS <- xhaz(
#'               formula = Surv(obs_time_year, event) ~ ageCentre + qbs(immuno_trt),
#'               data = dataCancer, ratetable = survexp.fr,
#'               interval = c(0, NA, NA, max(dataCancer$obs_time_year)),
#'               rmap = list(age = 'age', sex = 'sexx', year = 'year_date'),
#'               baseline = "bsplines", pophaz = "classic")
#'
#' print(fit.tdphBS)
#' }
#'
#' @export


qbs <- function(x){
  to.eval <- quote(x)
  evaluated <- eval(to.eval)
  return(evaluated)
  invisible()
}