In NumerousHats/currency: Convert, manipulate, and report monetary values

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

Generating a `currency` object

require(currency)

as.currency(20)

as.currency(200000000)

as.currency(200000000, type="JPY")

Arithmetic operations

The currency class inherits from the base R numeric class, so all of the standard arithmetic operations work as expected. The result is either of class currency or numeric, depending on what makes sense based on dimensional analysis: if the result has a meaningful currency unit under the assumption that any numeric participating in a binary arithmetic operation is dimensionless, then the result will be currency, otherwise it will be numeric.

twenty <- as.currency(20)
thirty <- as.currency(30)

twenty + thirty

twenty/0.001

10/twenty # numeric, would have units of "per dollar"

2*twenty

twenty*thirty # numeric, would have units of "dollar^2"

log10(thirty)

sqrt(twenty)

mean(c(twenty, thirty)) # what should this be?

Original currency values

The currency object extends the numeric class with two additional slots that store the original, uncoverted currency value and the original currency type.

yen <- as.currency(200, type="JPY")

yen

format(yen, original=TRUE)

For the results of an arithmetic operations that return currency, the original values are set appropriately if it makes sense to do so.

format(twenty + thirty, original=TRUE) # OK

format(twenty + yen, original=TRUE) # NO

format(2*yen, original=TRUE) # OK

format(yen/0.001, original=TRUE) # OK