R/numbers2words.R

In patelm9/cartographR:

numbers2words <- function(x){
        ## Function by John Fox found here: 
        ## http://tolstoy.newcastle.edu.au/R/help/05/04/2715.html
        ## Tweaks by AJH to add commas and "and"
        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 and", 
                                                  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 <- function(text){
                #Tidy leading/trailing whitespace, space before comma
                text=gsub("^\ ", "", gsub("\ *$", "", gsub("\ ,",",",text)))
                #Clear any trailing " and"
                text=gsub(" and$","",text)
                #Clear any trailing comma
                gsub("\ *,$","",text)
        }  
        makeNumber <- function(...) as.numeric(paste(..., collapse=""))     
        #Disable scientific notation
        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(trim(sapply(x, helper)))
        helper(x)
}