numbers2words

number2words.r

# John Fox's numbers2words found here: 
# http://tolstoy.newcastle.edu.au/R/help/05/04/2715.html
numbers2words <- function(x){
  # helper
  helper <- function(x){
    
    digits <- rev(strsplit(as.character(x), "")[[1]])
    nDigits <- length(digits)
    if (nDigits == 1) as.vector(ones[digits])
    else if (nDigits == 2)
      if (x <= 19) as.vector(teens[digits[1]])
    else trim(paste(tens[digits[2]],
                    Recall(as.numeric(digits[1]))))
    else if (nDigits == 3) trim(paste(ones[digits[3]], "hundred", 
                                      Recall(makeNumber(digits[2:1]))))
    else {
      nSuffix <- ((nDigits + 2) %/% 3) - 1
      if (nSuffix > length(suffixes)) stop(paste(x, "is too large!"))
      trim(paste(Recall(makeNumber(digits[
        nDigits:(3*nSuffix + 1)])),
        suffixes[nSuffix],  
        Recall(makeNumber(digits[(3*nSuffix):1]))))
    }
  }
  # trim
  trim <- function(text){
    gsub("^\ ", "", gsub("\ *$", "", text))
  }      
  
  # maekNum
  makeNumber <- function(...) as.numeric(paste(..., collapse=""))
  opts <- options(scipen=100) 
  on.exit(options(opts)) 
  ones <- c("", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine") 
  names(ones) <- 0:9
  teens <- c("ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", " seventeen", "eighteen", "nineteen")
  names(teens) <- 0:9 
  tens <- c("twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety") 
  names(tens) <- 2:9 
  x <- round(x) 
  suffixes <- c("thousand", "million", "billion", "trillion")     
  if (length(x) > 1) 
    return(sapply(x, helper))
  helper(x) 
}