R/load_iot.R

In sybrendeuzeman/WIOD_package: International Input Output Table Package

# Load the International Input Output Data from CSV files.
# For use in library WIOD

# Created by Sybren Deuzeman
# Maintained by GGDC

# First version: 3 May 2019
# Current Version: 11 june 2019

#' @title
#' Load a single International Input-Output Table.
#' 
#' @description 
#' Function loads a single internation Input-Output Table (IOT).
#'
#' @param version: version of IOT
#' @param year: year of IOT
#' @param directory: directory to where the input-output tables are stored. 
#' 
#' @details 
#' Versions currently supported are WIOD2013 (World Input Output Database, version 2013), 
#' WIOD2016 (World Input Output Database, version 2013) 
#' and ICIOT2018 (Inter-Country Input Output Tables, version 2018).
#' 
#' To load a time-series of international input-output tables use load_iots()
#' 
#' Directory only needs to direct to the main storage directory, right version and year will be taken care of. 
#' Default is loading via the internet. Users who use IOTs more often are advised to make a local copy.
#' Local copy of online data can be made via download_iots()
#'  
#' @examples
#' \dontrun{Using online data:}
#' iot <- load_iot("WIOD2013", 2000)
#' 
#' @examples
#' \dontrun{Using local data:
#' iot <- load_iot("WIOD2013", 2000, directory = "D:/Data")}
#' 
#'  
#' @export
load_iot <- function(version, year, directory = get("dir_data", envir = paramEnv)){
  # Make file directory
  dir_file = paste(directory, "/", version, "/", version, toString(year), ".rds", sep = "")
  
  # When loading from the internet
  if ( is_dir_http(dir_file) ){
    iot <- load_Rd_internet(dir_file)
    return(iot)
  }
  
  
  # When loading from local copy
  if( !is_dir_http(dir_file) ){
    if ( file.exists(dir_file) ){  # If file exists, load the file
      iot <- readRDS(dir_file)
      return(iot)
    }
    else{ # If file does not exist, download data first.
      print("Requested data not found. Trying to download data now.")
      download_iot(version , year , dir_data = directory) # If not downloadable, download_iot will handle that
      if (file.exists(dir_file)){ # If file downloaded, read file
        print("Found, downloaded and added.")
        iot <- readRDS(dir_file)
        return(iot)
      }
    }
  }
}