Question

Is there an already existing solution that can parse all the numbers below?

"300.00"
"2.300,00"
"2,300.00"

Answer 1

Try using the money gem:

$ gem install money

Then you can do:

require 'money'

test1 = Money.parse("300.00")
test2 = Money.parse("2.300,00")
test3 = Money.parse("2,300.00")

test1.currency # #<Money::Currency id: usd, priority: 1, symbol_first: true, thousands_separator: ,, html_entity: $, decimal_mark: ., name: United States Dollar, symbol: $, subunit_to_unit: 100, iso_code: USD, iso_numeric: 840, subunit: Cent>
test1.amount # 300.0
test1.dollars # 300.0
test1.cents # 30000
test1.currency_as_string # USD
test1.separator # .
test1.thousands_separator # ,
test1.delimiter # ,

EDIT: the old money gem has split into two parts: money and monetize. The new money class only handles creating, manipulating and converting currencies between money objects.

To parse objects (including strings) into money objects, you should use the monetize gem instead:

$ gem install monetize

Monetize.parse("USD 100")
Monetize.parse("£100")
Monetize.parse_collection("€80, $100")