R/check_data.R

In ahaeusser/tscv: Functions and utilities for tidy time series forecasting and time series cross-validation

#' @title Check, convert and shape the input data
#'
#' @description The function checks whether the input data are a valid tsibble or not (regular spaced in time
#'    and ordered). Furthermore, implicit missing values are turned into explicit missing values (existing
#'    missing values are left untouched). If the data are provided in wide format, they are pivoted into
#'    long format.
#'
#' @param data A valid tsibble, either in long or in wide format.
#' @param fill_missing Logical value. If \code{TRUE}, implicit missing values are turned into explicit missing values.
#'
#' @return data A valid tsibble in long format with one measurement variable.
#' @export

check_data <- function(data,
                       fill_missing = TRUE) {

  # Check input data
  if (is_tsibble(data) == FALSE) {
    stop("Please provide a tsibble (class tbl_ts).")
  }

  if (is_regular(data) == FALSE) {
    stop("The tsibble is not spaced at regular time.")
  }

  if (is_ordered(data) == FALSE) {
    stop("The tsibble is not ordered by key and index.")
  }

  # Turn implicit missing values into explicit missing values
  if (fill_missing == TRUE) {
    data <- data %>%
      fill_gaps(.full = TRUE)
  }

  # Check whether the data are in wide format and,
  # if necessary, gather to long format
  if (is_empty(key_vars(data)) == TRUE) {
    data <- data %>%
      gather(
        key = "variable",
        value = "value",
        -!!sym(index_var(data)))
  }

  return(data)
}