invacost_FUN/currency_exchange.R at main · InvaHealth/invacost_FUN · GitHub

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## Script to convert cost in local currency to USD
## written by Anna J. Turbelin, November 14, 2022
## aturbelin@gmail.com

library(knitr)
library(dplyr)
library(ggplot2)
library(devtools)
library(mgcv)
library(ggpubr)
library(readxl)
library(tidyverse)
library(ggpmisc)
install.packages("wbstats")
library(wbstats)
library(readr)
# library(OECD)
# library(countrycode)
# library(ISOcodes)


options(stringsAsFactors=FALSE)


## function 2.0 to adjust costs for inflation with option to have a 'neutral' fixed year' original CPI column
##' @param costdb Name of database to pull costs from that need to be converted.
##' @param costcolumn Name of the cost column to use in \code{costdb}. Original currency raw costs to be converted.
##' @param yearcolumn Name of the year column to use. This is the column that records the year when the costs were reported or when the currency is applicable.
##' @param currencycolumn Name of the currency column to use. This is the column that records the currency in which original costs were reported.
##' @param originalyear Year of the current cost value - use when @param yearcolumn is null because costs have already been standardized to a given year.
##' @param method Name of the method to use to convert costs to USD - currently method used in "WB" which is just the data from worldbank


currencyXchange <- function(costdb, costcolumn, yearcolumn = "Applicable_year",  currencycolumn = "Currency", originalyear = NULL, method = "WB"){

  if(is.null(costcolumn))
  {
    stop("Add column name of raw costs in local currency to convert to USD")
  }

  if(!(costcolumn %in% colnames(costdb)))
  {
    stop("The 'costcolumn' does not exist in the database, please check spelling.")
  }

  if(!(yearcolumn %in% colnames(costdb)))
  {
    stop("The 'yearcolumn' does not exist in the database, please check spelling.")
  }

  if(!(currencycolumn %in% colnames(costdb)))
  {
    stop("The 'currencycolumn' does not exist in the database, please check spelling.")
  }

  Xrate.dat <- wb_data("PA.NUS.FCRF", country = "all") ## get exchange rate data from world bank
  urlfile = "https://raw.githubusercontent.com/agitea/invacost_FUN/main/data/CurrencyName.csv"
  currency.name <- read_csv(url(urlfile))


    costUSD <- do.call(rbind,lapply(costdb$Cost_ID, function(x, costdb.,
                                                           cost,
                                                           year,
                                                           currency){

    currency.code = costdb.[which(costdb.$Cost_ID == x), currency]
    year.app = costdb.[which(costdb.$Cost_ID == x), year]
    currency.country <- currency.name[which(currency.name$Currency_code == currency.code), colnames(currency.name)=="ISO"]


    if(isTRUE(length(currency.country$ISO) == 0 & currency.code == "REA")){currency.country = "BRA"}else{
      if(isTRUE(length(currency.country$ISO) == 0 & currency.code == "SOL")){currency.country = "PER"}else{
        if(isTRUE(length(currency.country$ISO) == 0 & currency.code == "COL")){currency.country = "COL"}else{


          if(length(currency.country$ISO)>1){
            if(currency.code == "EUR"){currency.country = "EMU"} else {
              if(currency.code == "USD"){currency.country = "USA"} else {
                if(currency.code == "XPF"){currency.country = "NCL"} else {

                  currency.country <- currency.name[which(currency.name$Currency_code == currency.code & currency.name$country_type != "0" & currency.name$country_type != "Dependency"), colnames(currency.name)=="ISO"]
                  currency.country <-currency.country[1, colnames(currency.country)=="ISO"]
                }
              }
            }
          } else {currency.country <- currency.country[[1]]}

        }}}


    currency.country <- currency.country[[1]]

    Xchange.rate = Xrate.dat[which(Xrate.dat$iso3c == currency.country & Xrate.dat$date == year.app), colnames(Xrate.dat)=="PA.NUS.FCRF"]
    cost.raw.local = costdb.[which(costdb.$Cost_ID == x), cost]
    cost.USD <- cost.raw.local/Xchange.rate
    colnames(cost.USD) <- paste0("cost_USD")

    return(cost.USD)


  }, costdb. = costdb, cost = costcolumn, year = yearcolumn, currency = currencycolumn
  ))


  return(df <- data.frame(dplyr::bind_cols(costdb, costUSD))) #this returns a new data frame - probably best to add to current dataset but not 100% how to do it


}