R/fredr_category_series.R

In sboysel/fredr: An R Client for the 'FRED' API

#' Get the series in a category
#'
#' @param category_id An integer ID for the category.
#'
#' @param tag_names A string indicating which series tags to match.  Multiple
#' tags can be delimited by a semicolon in a single string (e.g. `"usa;gnp"`).
#'
#' @param exclude_tag_names A string indicating which series tags should _not_
#' be matched.  Multiple tags can be delimited by a semicolon in a single string
#' (e.g. `"usa;gnp"``).
#'
#' @param filter_variable A string indicating which attribute to indicate the
#' attribute that results are filtered by.  Possible values include: `"frequency"`,
#' `"units"`, `"seasonal_adjustment"`.  No filtering by default.
#'
#' @param filter_value A string giving the value of the `filter_variable`
#' attribute to filter results by.  `filter_variable` must be set.  No filtering
#' by default.
#'
#' @param limit An positive integer indicating maximum number of results to
#' return.  Possible values are any integer between `1` and `1000` (default),
#' inclusive.
#'
#' @param offset An non-negative integer used in conjunction with `limit` for
#' long series.  This mimics the idea of _pagination_ to retrieve large amounts
#' of data over multiple calls. Defaults to `0`.
#'
#' @param order_by A string indicating an attribute by which the results are
#' ordered by. Possible values include:
#'
#' * `"series_id"` (default)
#' * `"title"`
#' * `"units"`
#' * `"frequency"`
#' * `"seasonal_adjustment"`
#' * `"realtime_start"`
#' * `"realtime_end"`
#' * `"last_updated"`
#' * `"observation_start"`
#' * `"observation_end"`
#' * `"popularity"`
#' * `"group_popularity"`
#'
#' @param sort_order A string representing the order of the resulting series.
#' Possible values are: `"asc"` (default), and `"desc"`.
#'
#' @param realtime_start A `Date` indicating the start of the real-time period.
#' Defaults to today's date. For more information, see
#' [Real-Time Periods](https://fred.stlouisfed.org/docs/api/fred/realtime_period.html).
#'
#' @param realtime_end A `Date` indicating the end of the real-time period.
#' Defaults to today's date. For more information, see
#' [Real-Time Periods](https://fred.stlouisfed.org/docs/api/fred/realtime_period.html).
#'
#' @param ... These dots only exist for future extensions and should be empty.
#'
#' @return A `tibble` object with information for series matching the request for
#' the category specified in `category_id`.
#'
#' @section API Documentation:
#'
#' [fred/category/series](https://fred.stlouisfed.org/docs/api/fred/category_series.html)
#'
#' @seealso [fredr_category()], [fredr_category_children()], [fredr_category_related()],
#'  [fredr_category_tags()], [fredr_category_related_tags()]
#'
#' @examples
#' if (fredr_has_key()) {
#' # Top 10 most popular series belonging to the "Employment Cost Index" category
#' fredr_category_series(category_id = 1L, limit = 10L, order_by = "popularity")
#' # Series in the "Employment Cost Index" category, ordered by descending observation frequency
#' fredr_category_series(category_id = 4L, order_by = "frequency", sort_order = "desc")
#' }
#' @export
fredr_category_series <- function(category_id,
                                  ...,
                                  filter_variable = NULL,
                                  filter_value = NULL,
                                  tag_names = NULL,
                                  exclude_tag_names = NULL,
                                  limit = NULL,
                                  offset = NULL,
                                  order_by = NULL,
                                  sort_order = NULL,
                                  realtime_start = NULL,
                                  realtime_end = NULL) {
  check_dots_empty(...)
  check_not_null(category_id, "category_id")

  user_args <- capture_args(
    category_id = category_id,
    realtime_start = realtime_start,
    realtime_end = realtime_end,
    limit = limit,
    offset = offset,
    order_by = order_by,
    sort_order = sort_order,
    filter_variable = filter_variable,
    filter_value = filter_value,
    tag_names = tag_names,
    exclude_tag_names = exclude_tag_names
  )

  fredr_args <- list(
    endpoint = "category/series"
  )

  do.call(fredr_request, c(fredr_args, user_args))
}