Format String as Currency with Ruby/Sinatra

Question

I have an app in Ruby/Sinatra that uses an API to return a string that I need to format as currency but don't see any simple way to do this.

Specifically, I'd like a string 665778 to print out as $665,778

I tried implementing Sinatra::Numeric::Helpers but that didn't work and I suspect it's outdated. Please advise. There seems easy to do in Rails but not in Sinatra.

Possible duplicate of [What is the best method of handling currency/money?](http://stackoverflow.com/questions/1019939/what-is-the-best-method-of-handling-currency-money) — osman, Feb 22 '16 at 18:54
@osman not a duplicate because that answer is for rails. i'm using sinatra. the issue seems easier to handle in rails. — peacecoder, Feb 22 '16 at 19:01
Your question isn't clear. "format as currency" can mean a lot of different things. What is your expected result? `1234.56`? `£1,234.56`? `€ 1.234,56`? Something else? — Jordan Running, Feb 22 '16 at 19:10

score 3 · Accepted Answer · edited May 23 '17 at 11:45

3

I'd like a string 665778 to print out as $665,778

Borrowing the thousands-grouping code from this answer yields a succinct solution:

def number_to_currency(num)
  "$#{num.to_s.gsub(/\d(?=(...)+$)/, '\0,')}"
end

edited May 23 '17 at 11:45

Community

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answered Feb 23 '16 at 05:33

Jordan Running

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Great. Many thanks. Thought there might be a way to do this without using gsub/regex but looks like not. – peacecoder Feb 26 '16 at 15:02

score 0 · Answer 2 · answered Mar 16 '16 at 17:55

Try this function ... it's equivalent in Rails to number_to_currency:

def to_cash(unit = "R$",separator = ",",delimiter = ".")
    mystring = sprintf("%s %.2f",unit, self)
    mystring = mystring.gsub(".",separator)
    pos = mystring.match(separator).begin(0) - 3
    while !(/[0-9]/.match(mystring[pos])== nil) do
        mystring.insert(pos,delimiter)
        pos-=3
    end 
    return mystring
end

Format String as Currency with Ruby/Sinatra

2 Answers2