Question

Is there a way to force Rails to output all decimal numbers with a certain precision? All of the decimal fields in my database are currency amounts, so I’d like decimal numbers to show by default with a precision of 2 (i.e. 2.40). I know I can use a helper function like “number_to_currency” to do this to each individual number, but that seems a bit tedious and unnecessary.

Answer 1

If you’re concerned about overriding “to_s” on Float having possible unforeseen side-effects, your next best bet is probably to just create a new method, but still as a core extension. Something like this:

class Float
    def c
        sprintf('%.2f', self)
    end
end

Then can’t have any unforeseen consequences, and then anywhere you’d want to display the number with two decimal places, you’d just call .c. For example:

message = "The account balance is $#{amount.c}."

Not automatic, but not much extra typing, and no possible side-effects that overriding to_s could potentially cause.