R/fread_trips_data.R

In bysykkel: Get City Bike Data from Norway

#' @title Fast read historical bike trips data in Norway to R
#'
#' @description
#' \code{fread_trips_data()} imports anonymized historical bike trips data for
#' the city of Oslo, Bergen, and Trondheim, in Norway, directly to R.
#'
#' \code{fread_trips_data()} utilizes the
#' \code{\link[data.table:fread]{fread()}} function from the \code{data.table}
#' package to fast read the CSV-files. Hence, it is much faster than
#' \code{read_trips_data}. \code{fread_trips_data()} requires that you
#' have the \code{data.table} package installed.
#'
#' The data is provided according to the Norwegian License for Open Government
#' Data 2.0 (\href{https://data.norge.no/nlod/en/2.0}{NLOD 2.0}).
#'
#' The data is read from:
#'
#' \itemize{
#'   \item \href{https://oslobysykkel.no/en/open-data/historical}{Oslo City Bike}
#'   \item \href{https://bergenbysykkel.no/en/open-data/historical}{Bergen City Bike}
#'   \item \href{https://trondheimbysykkel.no/en/open-data/historical}{Trondheim City Bike}
#'}
#'
#' @usage
#' fread_trips_data(year, month, city)
#'
#' @param year
#' A number. The year that you want to download data for.
#'
#' @param month
#' A number. The month that you want to download data for.
#'
#' @param city
#' A string. The city you want to download data from. The options are
#' "Oslo", "Bergen", and "Trondheim".
#'
#' @return
#' The function reads in bike trips data for the specified year, month, and city
#' to R as a tibble.
#'
#' @examples
#' \dontrun{
#'
#' # Fast read bike trips data for the month of January 2019 in Bergen
#' bergen_trips <- fread_trips_data(year = 2019, month = 1, city = "Bergen")
#'
#' # Fast read bike trips data for the month of October 2018 in Trondheim
#' trondheim_trips <- fread_trips_data(2018, 10, "Trondheim")
#'
#' }
#'
#' @importFrom glue glue
#' @importFrom tibble as_tibble
#' @importFrom httr http_error
#' @importFrom lubridate month
#' @importFrom lubridate year
#' @importFrom utils read.csv
#' @importFrom utils unzip
#' @importFrom utils download.file
#' @export fread_trips_data

fread_trips_data <- function(year, month, city) {

  # Require `data.table` in namespace ---------------------------------------

  if (!requireNamespace("data.table", quietly = TRUE)) {
    stop("The package \"data.table\" is required for this function to work. ",
         "Please install it.")
  }

  # Control input arguments -------------------------------------------------

  bysykkel_control_input(year, month, city)

  bysykkel_control_date(year, month, city)

  message(glue::glue("Getting bike data for {city} for ",
                     "{lubridate::month(month, label = TRUE, abbr = FALSE)}, ",
                     "{year}."))

  # Control structure -------------------------------------------------------

  switch(city,
         "Oslo" = fread_trips_data_oslo(year, month),
         "Bergen" = fread_trips_data_bergen(year, month),
         "Trondheim" = fread_trips_data_trondheim(year, month),
         stop(paste0("\"", city, "\" is an invalid city name."))
  )

}