currency_converter.r

# File-Name:       currency_converter.R                 
# Date:            2009-11-17                                
# Author:          Drew Conway                                       
# Purpose:         Convert currency data
# Data Used:       vc_invests.csv
# Packages Used:   foreign,XML
# Output File:     vc_invests_USD.csv
# Data Output:     
# Machine:         Drew Conway's MacBook                         
                                                                    
library(foreign)
library(XML)

vc<-read.csv('vc_invests.csv')

currency.converter<-function(amount,from.currency,to.currency) {
    # Converts amount (numeric) from given currency (character) to
    # current USD equivalent.  Currency characters must match three-letter
    # currency codes (see here: http://www.xe.com/iso4217.php)
    search.url<-paste("http://www.xe.com/ucc/convert.cgi?To=",to.currency,"&From=",from.currency,"&Amount=",as.integer(amount),sep="")
    html<-capture.output(htmlTreeParse(search.url,isURL=TRUE))
    money.list<-unlist(strsplit(html[580],' '))
    return(as.numeric(gsub(",","",money.list[21])))
} 

for(c in 1:length(vc$currency)) {
    size<-as.numeric(vc$round_size[c])
    cur<-vc$currency[c]
    if(is.na(size)==FALSE & cur!="USD") {
        vc$round_size[c]<-currency.converter(size,cur,"USD")
        vc$currency[c]<-"USD"
   }
}

write.csv(vc,"vc_invests_USD.csv")

gistfile2.txt