R/mps_on_date.R

In parlitools: Tools for Analysing UK Politics

#' MPs on or between two dates
#'
#' Retrieve information on all MPs who were members of the House of Commons
#' on a date or between two dates.
#'
#' Returns information on all MPs who were members of the House of Commons on
#' the date specificed (if only one date is included as a parameter), or on or
#' between the two dates if both are specified. Includes constituency and
#' electoral information if the date is 2010-05-06 or later, or if the date
#' range is entirely between 2010-05-06 and the present day. This function
#' is identical to the `mnis_mps_on_date` function from
#' the `[mnis](https://cran.r-project.org/package=mnis)` package, except it
#' includes consituency data from the
#' 2010 General Election (on 2010-05-06) onwards.
#'
#' @param date1 The date to return the list of MPs from. Accepts character
#' values in `'YYYY-MM-DD'` format, and objects of class `Date`,
#' `POSIXt`, `POSIXct`, `POSIXlt` or anything else than can
#' be coerced to a date with `as.Date()`. Defaults to current system date.
#' @param date2 An optional query parameter. Accepts character values in
#' `'YYYY-MM-DD'` format, and objects of class `Date`,
#' `POSIXt`, `POSIXct`, `POSIXlt` or anything else than can
#' be coerced to a date with `as.Date()`. If a proper date, the function
#' returns a list of all MPs who were members between `date2` and
#' `date1`. Defaults to `NULL`.
#' @param tidy If `TRUE`, fixes the variable names in the tibble to
#' remove special characters and superfluous text, and converts the variable
#' names to a consistent style. Defaults to `TRUE`.
#' @param tidy_style The style to convert variable names to,
#' if `tidy = TRUE`. Accepts one of `'snake_case'`,
#' `'camelCase'` and `'period.case'`. Defaults to `'snake_case'`.
#'
#' @return A tibble with information on all MPs who were members of the House
#' of Commons on the date specificed (if only `date1` is included as a
#' parameter), or on or between the two dates if both `date1` and
#' `date2` are specified.
#' @export
#'
#' @examples \dontrun{
#' x <- mps_on_date(date1 = "2017-04-19", date2 = "2010-05-04")
#' }

mps_on_date <- function(date1 = Sys.Date(), date2 = NULL,
                        tidy = TRUE, tidy_style = "snake_case") {
  date1 <- as.Date(date1)

  if (is.null(date2) == FALSE) {
    date2 <- as.Date(date2)
  }

  if (is.null(date2) == TRUE) {
    date2 <- date1
  } else if (date1 > date2) {
    date3 <- date1

    date1 <- date2

    date2 <- date3

    rm(date3)
  }

  mps <- mnis::mnis_mps_on_date(
    date1 = date1, date2 = date2,
    tidy = tidy, tidy_style = tidy_style
  )
  ## As the API only works for the 2010 General Election onwards
  if (date1 >= "2010-05-06") {
    mps <- parlitools_tidy(mps, tidy_style = "snake_case")

    message("Downloading constituency data")

    suppressMessages(constit <- hansard::constituencies(current = TRUE))

    suppressMessages(elect <- hansard::elections())

    elect$about <- gsub("http://data.parliament.uk/resources/", "", elect$about)

    suppressMessages(elect_res <- hansard::election_results())

    elect_res$election_about <- gsub(
      "http://data.parliament.uk/resources/",
      "", elect_res$election_about
    )

    elect_res2 <- dplyr::left_join(elect_res, elect,
      by = c("election_about" = "about")
    )

    elect_res2 <- elect_res2[elect_res2$date_value <= date2, ]

    elect_res2 <- elect_res2[rev(order(elect_res2$date_value)), ]

    elect_res2 <- subset(
      elect_res2,
      !duplicated(elect_res2$constituency_about)
    )

    constit$about <- gsub(
      "http://data.parliament.uk/resources/",
      "", constit$about
    )

    const_elect <- dplyr::left_join(constit, elect_res2,
      by = c("about" = "constituency_about")
    )

    df <- dplyr::left_join(mps, const_elect,
      by = c("member_from" = "constituency_label_value")
    )

    df$label_value.y <- NULL
    df$label_value.x <- NULL
    df$about.y <- NULL
    df$about.y.y <- NULL
    df$os_name <- NULL

    if (tidy == TRUE) {
      df <- parlitools_tidy(df, tidy_style)
    }

    df
  } else {
    if (tidy == TRUE) {
      mps <- parlitools_tidy(mps, tidy_style)
    }

    mps
  }
}