# File activesupport/lib/active_support/core_ext/numeric/conversions.rb, line 102
def to_s(format = nil, options = nil)
  case format
  when nil
    super()
  when Integer, String
    super(format)
  when :phone
    return ActiveSupport::NumberHelper.number_to_phone(self, options || {})
  when :currency
    return ActiveSupport::NumberHelper.number_to_currency(self, options || {})
  when :percentage
    return ActiveSupport::NumberHelper.number_to_percentage(self, options || {})
  when :delimited
    return ActiveSupport::NumberHelper.number_to_delimited(self, options || {})
  when :rounded
    return ActiveSupport::NumberHelper.number_to_rounded(self, options || {})
  when :human
    return ActiveSupport::NumberHelper.number_to_human(self, options || {})
  when :human_size
    return ActiveSupport::NumberHelper.number_to_human_size(self, options || {})
  when Symbol
    super()
  else
    super(format)
  end
end

Provides options for converting numbers into formatted strings. Options are provided for phone numbers, currency, percentage, precision, positional notation, file size and pretty printing.

Options

For details on which formats use which options, see ActiveSupport::NumberHelper

Examples

Phone Numbers:
5551234.to_s(:phone)                                     # => "555-1234"
1235551234.to_s(:phone)                                  # => "123-555-1234"
1235551234.to_s(:phone, area_code: true)                 # => "(123) 555-1234"
1235551234.to_s(:phone, delimiter: ' ')                  # => "123 555 1234"
1235551234.to_s(:phone, area_code: true, extension: 555) # => "(123) 555-1234 x 555"
1235551234.to_s(:phone, country_code: 1)                 # => "+1-123-555-1234"
1235551234.to_s(:phone, country_code: 1, extension: 1343, delimiter: '.')
# => "+1.123.555.1234 x 1343"

Currency:
1234567890.50.to_s(:currency)                 # => "$1,234,567,890.50"
1234567890.506.to_s(:currency)                # => "$1,234,567,890.51"
1234567890.506.to_s(:currency, precision: 3)  # => "$1,234,567,890.506"
1234567890.506.to_s(:currency, locale: :fr)   # => "1 234 567 890,51 €"
-1234567890.50.to_s(:currency, negative_format: '(%u%n)')
# => "($1,234,567,890.50)"
1234567890.50.to_s(:currency, unit: '£', separator: ',', delimiter: '')
# => "£1234567890,50"
1234567890.50.to_s(:currency, unit: '£', separator: ',', delimiter: '', format: '%n %u')
# => "1234567890,50 £"

Percentage:
100.to_s(:percentage)                                  # => "100.000%"
100.to_s(:percentage, precision: 0)                    # => "100%"
1000.to_s(:percentage, delimiter: '.', separator: ',') # => "1.000,000%"
302.24398923423.to_s(:percentage, precision: 5)        # => "302.24399%"
1000.to_s(:percentage, locale: :fr)                    # => "1 000,000%"
100.to_s(:percentage, format: '%n  %')                 # => "100.000  %"

Delimited:
12345678.to_s(:delimited)                     # => "12,345,678"
12345678.05.to_s(:delimited)                  # => "12,345,678.05"
12345678.to_s(:delimited, delimiter: '.')     # => "12.345.678"
12345678.to_s(:delimited, delimiter: ',')     # => "12,345,678"
12345678.05.to_s(:delimited, separator: ' ')  # => "12,345,678 05"
12345678.05.to_s(:delimited, locale: :fr)     # => "12 345 678,05"
98765432.98.to_s(:delimited, delimiter: ' ', separator: ',')
# => "98 765 432,98"

Rounded:
111.2345.to_s(:rounded)                                      # => "111.235"
111.2345.to_s(:rounded, precision: 2)                        # => "111.23"
13.to_s(:rounded, precision: 5)                              # => "13.00000"
389.32314.to_s(:rounded, precision: 0)                       # => "389"
111.2345.to_s(:rounded, significant: true)                   # => "111"
111.2345.to_s(:rounded, precision: 1, significant: true)     # => "100"
13.to_s(:rounded, precision: 5, significant: true)           # => "13.000"
111.234.to_s(:rounded, locale: :fr)                          # => "111,234"
13.to_s(:rounded, precision: 5, significant: true, strip_insignificant_zeros: true)
# => "13"
389.32314.to_s(:rounded, precision: 4, significant: true)    # => "389.3"
1111.2345.to_s(:rounded, precision: 2, separator: ',', delimiter: '.')
# => "1.111,23"

Human-friendly size in Bytes:
123.to_s(:human_size)                                   # => "123 Bytes"
1234.to_s(:human_size)                                  # => "1.21 KB"
12345.to_s(:human_size)                                 # => "12.1 KB"
1234567.to_s(:human_size)                               # => "1.18 MB"
1234567890.to_s(:human_size)                            # => "1.15 GB"
1234567890123.to_s(:human_size)                         # => "1.12 TB"
1234567890123456.to_s(:human_size)                      # => "1.1 PB"
1234567890123456789.to_s(:human_size)                   # => "1.07 EB"
1234567.to_s(:human_size, precision: 2)                 # => "1.2 MB"
483989.to_s(:human_size, precision: 2)                  # => "470 KB"
1234567.to_s(:human_size, precision: 2, separator: ',') # => "1,2 MB"
1234567890123.to_s(:human_size, precision: 5)           # => "1.1228 TB"
524288000.to_s(:human_size, precision: 5)               # => "500 MB"

Human-friendly format:
123.to_s(:human)                                       # => "123"
1234.to_s(:human)                                      # => "1.23 Thousand"
12345.to_s(:human)                                     # => "12.3 Thousand"
1234567.to_s(:human)                                   # => "1.23 Million"
1234567890.to_s(:human)                                # => "1.23 Billion"
1234567890123.to_s(:human)                             # => "1.23 Trillion"
1234567890123456.to_s(:human)                          # => "1.23 Quadrillion"
1234567890123456789.to_s(:human)                       # => "1230 Quadrillion"
489939.to_s(:human, precision: 2)                      # => "490 Thousand"
489939.to_s(:human, precision: 4)                      # => "489.9 Thousand"
1234567.to_s(:human, precision: 4,
                 significant: false)                   # => "1.2346 Million"
1234567.to_s(:human, precision: 1,
                 separator: ',',
                 significant: false)                   # => "1,2 Million"