Represent numeric value with typical dollar amount format

Question

I have a data frame storing the dollar amount, it looks like this

> a   cost 1 1e+05 2 2e+05 

I would like it can be shown as this

> a     cost 1 $100,000 2 $200,000 

How to do that in R?

Answer 1

DF <- data.frame(cost=c(1e4, 2e5))  #assign a class     class(DF$cost) <- c("money", class(DF$cost))  #S3 print method for the class     print.money <- function(x, ...) {   print.default(paste0("$", formatC(as.numeric(x), format="f", digits=2, big.mark=","))) }  #format method, which is necessary for formating in a data.frame    format.money  <- function(x, ...) {   paste0("$", formatC(as.numeric(x), format="f", digits=2, big.mark=",")) }  DF #         cost #1  $10,000.00 #2 $200,000.00 

Answer 2

This will get you everything except the commas:

> sprintf("$%.2f", seq(100,100000,by=10000)/7)  [1] "$14.29"    "$1442.86"  "$2871.43"  "$4300.00"  "$5728.57"  "$7157.14"  "$8585.71"  "$10014.29" "$11442.86" "$12871.43" 

Getting those is pretty complicated, as shown in these questions:

• How can I format currency with commas in C?
• How to format a number from 1123456789 to 1,123,456,789 in C?

Luckily, this is implemented in the scales package:

library('scales') > dollar_format()(c(100, 0.23, 1.456565, 2e3)) ## [1] "$100.00"   "$0.23"     "$1.46"     "$2,000.00" > dollar_format()(c(1:10 * 10)) ## [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100" > dollar(c(100, 0.23, 1.456565, 2e3)) ## [1] "$100.00"   "$0.23"     "$1.46"     "$2,000.00" > dollar(c(1:10 * 10)) ## [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100" > dollar(10^(1:8)) ## [1] "$10"          "$100"         "$1,000"       "$10,000"      "$100,000"     "$1,000,000"   "$10,000,000"  "$100,000,000"