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

<

Answer 1

You can use the currency() function from the formattable package. With OP's example

a <- data.frame(cost = c(1e+05, 2e+05))
a

   cost
1 1e+05
2 2e+05

library(formattable)
a$cost <- currency(a$cost, digits = 0L)
a

      cost
1 $100,000
2 $200,000

By default, 2 digits after the decimal point are shown. This has been overruled using the digits parameter to meet OP's expectations.

The benfit of formattable is that numbers are still numbers even with a format attached, e.g.,

a$cost2 <- 2 * a$cost
a

      cost    cost2
1 $100,000 $200,000
2 $200,000 $400,000