R/extract.R

In associatedpress/ipedals: ipedals

#' Load the data CSV from an IPEDS zip file.
#'
#' @importFrom magrittr %>%
#' @param local_path The path to a downloaded zip file.
#' @param column_types A column specification as returned by `readr::cols`.
#' @return A tibble of data.
extract_csv <- function(local_path, column_types) {
  Name = lazyeval::as_name("Name")
  csv_filenames <- utils::unzip(local_path, list = TRUE) %>%
    tibble::as_tibble() %>%
    dplyr::filter(stringr::str_detect(Name, "\\.csv$"))
  csv_filename <- csv_filenames[1,]$Name
  csv_conn <- unz(local_path, csv_filename)
  parsed <- suppressWarnings(
    readr::read_csv(csv_conn, col_types = column_types)) %>%
    resolve_problems(csv_filename)
}

#' Load the column type/title metadata from an IPEDS zip file.
#'
#' @importFrom magrittr %>%
#' @param local_path The path to a downloaded zip file.
#' @param sheet_name Name of the sheet to extract from the Excel file contained
#'   in the zip.
#' @return A tibble of data.
extract_metadata_sheet <- function(local_path, sheet_name) {
  Name = lazyeval::as_name("Name")
  xlsx_filenames <- utils::unzip(local_path, list = TRUE) %>%
    tibble::as_tibble() %>%
    dplyr::filter(stringr::str_detect(Name, "\\.xlsx?$"))
  xlsx_filename <- xlsx_filenames[1,]$Name
  local_dir <- dirname(local_path)
  utils::unzip(local_path, xlsx_filename, exdir = local_dir)
  readxl::read_excel(file.path(local_dir, xlsx_filename), sheet = sheet_name)
}

#' Load the column type/title metadata from an IPEDS zip file.
#'
#' @param local_path The path to a downloaded zip file.
#' @return A tibble of data.
extract_varlist <- function(local_path) {
  extract_metadata_sheet(local_path, "varlist")
}

#' Load the codebook from an IPEDS zip file.
#'
#' @param local_path The path to a downloaded zip file.
#' @return A tibble of data.
extract_codebook <- function(local_path) {
  extract_metadata_sheet(local_path, "Frequencies")
}