Humanize numbers with Ruby

Install
#config/initializers/numeric_humanize.rb

 1  class Numeric
 2    def humanize(rounding=2,delimiter=',',separator='.')
 3      value = respond_to?(:round_with_precision) ? round(rounding) : self
 4 
 5      #see number with delimeter
 6      parts = value.to_s.split('.')
 7      parts[0].gsub!(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{delimiter}")
 8      parts.join separator
 9    end
10  end

Usage:
puts 1.humanize
#=> 1
puts 1000000.humanize
#=> 1,000,000
puts 1000.12345.humanize
#=> 1,000.12345