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

Most methods expect a number argument, and will return it unchanged if can’t be converted into a valid number.

Namespace
Methods
N
Constants
DEFAULT_CURRENCY_VALUES = { :format => "%u%n", :negative_format => "-%u%n", :unit => "$", :separator => ".", :delimiter => ",", :precision => 2, :significant => false, :strip_insignificant_zeros => false }
 
STORAGE_UNITS = [:byte, :kb, :mb, :gb, :tb].freeze
 
DECIMAL_UNITS = {0 => :unit, 1 => :ten, 2 => :hundred, 3 => :thousand, 6 => :million, 9 => :billion, 12 => :trillion, 15 => :quadrillion, -1 => :deci, -2 => :centi, -3 => :mili, -6 => :micro, -9 => :nano, -12 => :pico, -15 => :femto}.freeze
 
Instance Public methods
number_to_currency(number, options = {})

Formats a number into a currency string (e.g., $13.65). You can customize the format in the options hash.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :precision - Sets the level of precision (defaults to 2).

  • :unit - Sets the denomination of the currency (defaults to "$").

  • :separator - Sets the separator between the units (defaults to ".").

  • :delimiter - Sets the thousands delimiter (defaults to ",").

  • :format - Sets the format for non-negative numbers (defaults to "%u%n").

    Fields are <tt>%u</tt> for the currency, and <tt>%n</tt>
for the number.

  • :negative_format - Sets the format for negative numbers (defaults to prepending

    an hyphen to the formatted number given by <tt>:format</tt>).
Accepts the same fields than <tt>:format</tt>, except
<tt>%n</tt> is here the absolute value of the number.

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_to_currency(1234567890.50)                    # => $1,234,567,890.50
number_to_currency(1234567890.506)                   # => $1,234,567,890.51
number_to_currency(1234567890.506, :precision => 3)  # => $1,234,567,890.506
number_to_currency(1234567890.506, :locale => :fr)   # => 1 234 567 890,51 €
number_to_currency("123a456")                        # => $123a456

number_to_currency("123a456", :raise => true)        # => InvalidNumberError

number_to_currency(-1234567890.50, :negative_format => "(%u%n)")
# => ($1,234,567,890.50)
number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "")
# => &pound;1234567890,50
number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "", :format => "%n %u")
# => 1234567890,50 &pound;

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 123
def number_to_currency(number, options = {})
  return unless number

  options.symbolize_keys!

  defaults  = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  currency  = I18n.translate(:'number.currency.format', :locale => options[:locale], :default => {})
  currency[:negative_format] ||= "-" + currency[:format] if currency[:format]

  defaults  = DEFAULT_CURRENCY_VALUES.merge(defaults).merge!(currency)
  defaults[:negative_format] = "-" + options[:format] if options[:format]
  options   = defaults.merge!(options)

  unit      = options.delete(:unit)
  format    = options.delete(:format)

  if number.to_f < 0
    format = options.delete(:negative_format)
    number = number.respond_to?("abs") ? number.abs : number.sub(%r^-/, '')
  end

  begin
    value = number_with_precision(number, options.merge(:raise => true))
    format.gsub(%r%n/, value).gsub(%r%u/, unit).html_safe
  rescue InvalidNumberError => e
    if options[:raise]
      raise
    else
      formatted_number = format.gsub(%r%n/, e.number).gsub(%r%u/, unit)
      e.number.to_s.html_safe? ? formatted_number.html_safe : formatted_number
    end
  end

end
number_to_human(number, options = {})

Pretty prints (formats and approximates) a number in a way it is more readable by humans (eg.: 1200000000 becomes “1.2 Billion”). This is useful for numbers that can get very large (and too hard to read).

See number_to_human_size if you want to print a file size.

You can also define you own unit-quantifier names if you want to use other decimal units (eg.: 1500 becomes “1.5 kilometers”, 0.150 becomes “150 milliliters”, etc). You may define a wide range of unit quantifiers, even fractional ones (centi, deci, mili, etc).

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :precision - Sets the precision of the number (defaults to 3).

  • :significant - If true, precision will be the # of significant_digits. If false, the # of fractional digits (defaults to true)

  • :separator - Sets the separator between the fractional and integer digits (defaults to ".").

  • :delimiter - Sets the thousands delimiter (defaults to "").

  • :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator (defaults to true)

  • :units - A Hash of unit quantifier names. Or a string containing an i18n scope where to find this hash. It might have the following keys:

    • integers: :unit, :ten, :hundred, :thousand, :million, :billion, :trillion, :quadrillion

    • fractionals: :deci, :centi, :mili, :micro, :nano, :pico, :femto

  • :format - Sets the format of the output string (defaults to "%n %u"). The field types are:

    %u  The quantifier (ex.: 'thousand')
%n  The number

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

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

Unsignificant zeros after the decimal separator are stripped out by default (set :strip_insignificant_zeros to false to change that):

number_to_human(12345012345, :significant_digits => 6)       # => "12.345 Billion"
number_to_human(500000000, :precision => 5)                  # => "500 Million"

Custom Unit Quantifiers

You can also use your own custom unit quantifiers:

number_to_human(500000, :units => {:unit => "ml", :thousand => "lt"})  # => "500 lt"

If in your I18n locale you have:

distance:
  centi:
    one: "centimeter"
    other: "centimeters"
  unit:
    one: "meter"
    other: "meters"
  thousand:
    one: "kilometer"
    other: "kilometers"
  billion: "gazillion-distance"

Then you could do:

number_to_human(543934, :units => :distance)                              # => "544 kilometers"
number_to_human(54393498, :units => :distance)                            # => "54400 kilometers"
number_to_human(54393498000, :units => :distance)                         # => "54.4 gazillion-distance"
number_to_human(343, :units => :distance, :precision => 1)                # => "300 meters"
number_to_human(1, :units => :distance)                                   # => "1 meter"
number_to_human(0.34, :units => :distance)                                # => "34 centimeters"

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 483
def number_to_human(number, options = {})
  options.symbolize_keys!

  number = begin
    Float(number)
  rescue ArgumentError, TypeError
    if options[:raise]
      raise InvalidNumberError, number
    else
      return number
    end
  end

  defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  human    = I18n.translate(:'number.human.format', :locale => options[:locale], :default => {})
  defaults = defaults.merge(human)

  options = options.reverse_merge(defaults)
  #for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
  options[:strip_insignificant_zeros] = true if not options.key?(:strip_insignificant_zeros)

  inverted_du = DECIMAL_UNITS.invert

  units = options.delete :units
  unit_exponents = case units
  when Hash
    units
  when String, Symbol
    I18n.translate(:"#{units}", :locale => options[:locale], :raise => true)
  when nil
    I18n.translate(:"number.human.decimal_units.units", :locale => options[:locale], :raise => true)
  else
    raise ArgumentError, ":units must be a Hash or String translation scope."
  end.keys.map{|e_name| inverted_du[e_name] }.sort_by{|e| -e}

  number_exponent = number != 0 ? Math.log10(number.abs).floor : 0
  display_exponent = unit_exponents.find{ |e| number_exponent >= e } || 0
  number  /= 10 ** display_exponent

  unit = case units
  when Hash
    units[DECIMAL_UNITS[display_exponent]]
  when String, Symbol
    I18n.translate(:"#{units}.#{DECIMAL_UNITS[display_exponent]}", :locale => options[:locale], :count => number.to_i)
  else
    I18n.translate(:"number.human.decimal_units.units.#{DECIMAL_UNITS[display_exponent]}", :locale => options[:locale], :count => number.to_i)
  end

  decimal_format = options[:format] || I18n.translate(:'number.human.decimal_units.format', :locale => options[:locale], :default => "%n %u")
  formatted_number = number_with_precision(number, options)
  decimal_format.gsub(%r%n/, formatted_number).gsub(%r%u/, unit).strip.html_safe
end
number_to_human_size(number, options = {})

Formats the bytes in number into a more understandable representation (e.g., giving it 1500 yields 1.5 KB). This method is useful for reporting file sizes to users. You can customize the format in the options hash.

See number_to_human if you want to pretty-print a generic number.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :precision - Sets the precision of the number (defaults to 3).

  • :significant - If true, precision will be the # of significant_digits. If false, the # of fractional digits (defaults to true)

  • :separator - Sets the separator between the fractional and integer digits (defaults to ".").

  • :delimiter - Sets the thousands delimiter (defaults to "").

  • :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator (defaults to true)

  • :prefix - If :si formats the number using the SI prefix (defaults to :binary)

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_to_human_size(123)                                          # => 123 Bytes
number_to_human_size(1234)                                         # => 1.21 KB
number_to_human_size(12345)                                        # => 12.1 KB
number_to_human_size(1234567)                                      # => 1.18 MB
number_to_human_size(1234567890)                                   # => 1.15 GB
number_to_human_size(1234567890123)                                # => 1.12 TB
number_to_human_size(1234567, :precision => 2)                     # => 1.2 MB
number_to_human_size(483989, :precision => 2)                      # => 470 KB
number_to_human_size(1234567, :precision => 2, :separator => ',')  # => 1,2 MB

Non-significant zeros after the fractional separator are stripped out by default (set :strip_insignificant_zeros to false to change that):

number_to_human_size(1234567890123, :precision => 5)        # => "1.1229 TB"
number_to_human_size(524288000, :precision => 5)            # => "500 MB"

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 363
def number_to_human_size(number, options = {})
  options.symbolize_keys!

  number = begin
    Float(number)
  rescue ArgumentError, TypeError
    if options[:raise]
      raise InvalidNumberError, number
    else
      return number
    end
  end

  defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  human    = I18n.translate(:'number.human.format', :locale => options[:locale], :default => {})
  defaults = defaults.merge(human)

  options = options.reverse_merge(defaults)
  #for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
  options[:strip_insignificant_zeros] = true if not options.key?(:strip_insignificant_zeros)

  storage_units_format = I18n.translate(:'number.human.storage_units.format', :locale => options[:locale], :raise => true)

  base = options[:prefix] == :si ? 1000 : 1024

  if number.to_i < base
    unit = I18n.translate(:'number.human.storage_units.units.byte', :locale => options[:locale], :count => number.to_i, :raise => true)
    storage_units_format.gsub(%r%n/, number.to_i.to_s).gsub(%r%u/, unit).html_safe
  else
    max_exp  = STORAGE_UNITS.size - 1
    exponent = (Math.log(number) / Math.log(base)).to_i # Convert to base
    exponent = max_exp if exponent > max_exp # we need this to avoid overflow for the highest unit
    number  /= base ** exponent

    unit_key = STORAGE_UNITS[exponent]
    unit = I18n.translate(:"number.human.storage_units.units.#{unit_key}", :locale => options[:locale], :count => number, :raise => true)

    formatted_number = number_with_precision(number, options)
    storage_units_format.gsub(%r%n/, formatted_number).gsub(%r%u/, unit).html_safe
  end
end
number_to_percentage(number, options = {})

Formats a number as a percentage string (e.g., 65%). You can customize the format in the options hash.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current

    locale).

  • :precision - Sets the precision of the number (defaults to 3).

  • :significant - If true, precision will be the # of significant_digits. If false,

    the # of fractional digits (defaults to +false+).

  • :separator - Sets the separator between the fractional and integer digits (defaults

    to ".").

  • :delimiter - Sets the thousands delimiter (defaults to "").

  • :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator

    (defaults to +false+).

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_to_percentage(100)                                        # => 100.000%
number_to_percentage("98")                                       # => 98.000%
number_to_percentage(100, :precision => 0)                       # => 100%
number_to_percentage(1000, :delimiter => '.', :separator => ',') # => 1.000,000%
number_to_percentage(302.24398923423, :precision => 5)           # => 302.24399%
number_to_percentage(1000, :locale => :fr)                       # => 1 000,000%
number_to_percentage("98a")                                      # => 98a%

number_to_percentage("98a", :raise => true)                      # => InvalidNumberError

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 185
def number_to_percentage(number, options = {})
  return unless number

  options.symbolize_keys!

  defaults   = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  percentage = I18n.translate(:'number.percentage.format', :locale => options[:locale], :default => {})
  defaults  = defaults.merge(percentage)

  options = options.reverse_merge(defaults)

  begin
    "#{number_with_precision(number, options.merge(:raise => true))}%".html_safe
  rescue InvalidNumberError => e
    if options[:raise]
      raise
    else
      e.number.to_s.html_safe? ? "#{e.number}%".html_safe : "#{e.number}%"
    end
  end
end
number_to_phone(number, options = {})

Formats a number into a US phone number (e.g., (555) 123-9876). You can customize the format in the options hash.

Options

  • :area_code - Adds parentheses around the area code.

  • :delimiter - Specifies the delimiter to use (defaults to "-").

  • :extension - Specifies an extension to add to the end of the

    generated number.

  • :country_code - Sets the country code for the phone number.

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_to_phone(5551234)                                           # => 555-1234
number_to_phone("5551234")                                         # => 555-1234
number_to_phone(1235551234)                                        # => 123-555-1234
number_to_phone(1235551234, :area_code => true)                    # => (123) 555-1234
number_to_phone(1235551234, :delimiter => " ")                     # => 123 555 1234
number_to_phone(1235551234, :area_code => true, :extension => 555) # => (123) 555-1234 x 555
number_to_phone(1235551234, :country_code => 1)                    # => +1-123-555-1234
number_to_phone("123a456")                                         # => 123a456

number_to_phone("1234a567", :raise => true)                        # => InvalidNumberError

number_to_phone(1235551234, :country_code => 1, :extension => 1343, :delimiter => ".")
# => +1.123.555.1234 x 1343

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 58
def number_to_phone(number, options = {})
  return unless number

  begin
    Float(number)
  rescue ArgumentError, TypeError
    raise InvalidNumberError, number
  end if options[:raise]

  number       = number.to_s.strip
  options      = options.symbolize_keys
  area_code    = options[:area_code]
  delimiter    = options[:delimiter] || "-"
  extension    = options[:extension]
  country_code = options[:country_code]

  if area_code
    number.gsub!(%r(\d{1,3})(\d{3})(\d{4}$)/,"(\\1) \\2#{delimiter}\\3")
  else
    number.gsub!(%r(\d{0,3})(\d{3})(\d{4})$/,"\\1#{delimiter}\\2#{delimiter}\\3")
    number.slice!(0, 1) if number.starts_with?(delimiter) && !delimiter.blank?
  end

  str = []
  str << "+#{country_code}#{delimiter}" unless country_code.blank?
  str << number
  str << " x #{extension}" unless extension.blank?
  ERB::Util.html_escape(str.join)
end
number_with_delimiter(number, options = {})

Formats a number with grouped thousands using delimiter (e.g., 12,324). You can customize the format in the options hash.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :delimiter - Sets the thousands delimiter (defaults to ",").

  • :separator - Sets the separator between the fractional and integer digits (defaults to ".").

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_with_delimiter(12345678)                        # => 12,345,678
number_with_delimiter("123456")                        # => 123,456
number_with_delimiter(12345678.05)                     # => 12,345,678.05
number_with_delimiter(12345678, :delimiter => ".")     # => 12.345.678
number_with_delimiter(12345678, :delimiter => ",")     # => 12,345,678
number_with_delimiter(12345678.05, :separator => " ")  # => 12,345,678 05
number_with_delimiter(12345678.05, :locale => :fr)     # => 12 345 678,05
number_with_delimiter("112a")                          # => 112a
number_with_delimiter(98765432.98, :delimiter => " ", :separator => ",")
# => 98 765 432,98

number_with_delimiter("112a", :raise => true)          # => raise InvalidNumberError

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 231
def number_with_delimiter(number, options = {})
  options.symbolize_keys!

  begin
    Float(number)
  rescue ArgumentError, TypeError
    if options[:raise]
      raise InvalidNumberError, number
    else
      return number
    end
  end

  defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  options = options.reverse_merge(defaults)

  parts = number.to_s.to_str.split('.')
  parts[0].gsub!(%r(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{options[:delimiter]}")
  parts.join(options[:separator]).html_safe

end
number_with_precision(number, options = {})

Formats a number with the specified level of :precision (e.g., 112.32 has a precision of 2 if :significant is false, and 5 if :significant is true). You can customize the format in the options hash.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :precision - Sets the precision of the number (defaults to 3).

  • :significant - If true, precision will be the # of significant_digits. If false,

    the # of fractional digits (defaults to +false+).

  • :separator - Sets the separator between the fractional and integer digits (defaults

    to ".").

  • :delimiter - Sets the thousands delimiter (defaults to "").

  • :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator

    (defaults to +false+).

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

Examples

number_with_precision(111.2345)                                            # => 111.235
number_with_precision(111.2345, :precision => 2)                           # => 111.23
number_with_precision(13, :precision => 5)                                 # => 13.00000
number_with_precision(389.32314, :precision => 0)                          # => 389
number_with_precision(111.2345, :significant => true)                      # => 111
number_with_precision(111.2345, :precision => 1, :significant => true)     # => 100
number_with_precision(13, :precision => 5, :significant => true)           # => 13.000
number_with_precision(111.234, :locale => :fr)                             # => 111,234

number_with_precision(13, :precision => 5, :significant => true, :strip_insignificant_zeros => true)
# => 13

number_with_precision(389.32314, :precision => 4, :significant => true)    # => 389.3
number_with_precision(1111.2345, :precision => 2, :separator => ',', :delimiter => '.')
# => 1.111,23

Source: show | on GitHub 

# File actionpack/lib/action_view/helpers/number_helper.rb, line 285
def number_with_precision(number, options = {})
  options.symbolize_keys!

  number = begin
    Float(number)
  rescue ArgumentError, TypeError
    if options[:raise]
      raise InvalidNumberError, number
    else
      return number
    end
  end

  defaults           = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
  precision_defaults = I18n.translate(:'number.precision.format', :locale => options[:locale], :default => {})
  defaults           = defaults.merge(precision_defaults)

  options = options.reverse_merge(defaults)  # Allow the user to unset default values: Eg.: :significant => false
  precision = options.delete :precision
  significant = options.delete :significant
  strip_insignificant_zeros = options.delete :strip_insignificant_zeros

  if significant and precision > 0
    if number == 0
      digits, rounded_number = 1, 0
    else
      digits = (Math.log10(number.abs) + 1).floor
      rounded_number = (BigDecimal.new(number.to_s) / BigDecimal.new((10 ** (digits - precision)).to_f.to_s)).round.to_f * 10 ** (digits - precision)
      digits = (Math.log10(rounded_number.abs) + 1).floor # After rounding, the number of digits may have changed
    end
    precision -= digits
    precision = precision > 0 ? precision : 0  #don't let it be negative
  else
    rounded_number = BigDecimal.new(number.to_s).round(precision).to_f
  end
  formatted_number = number_with_delimiter("%01.#{precision}f" % rounded_number, options)
  if strip_insignificant_zeros
    escaped_separator = Regexp.escape(options[:separator])
    formatted_number.sub(%r(#{escaped_separator})(\d*[1-9])?0+\z/, '\1\2').sub(%r#{escaped_separator}\z/, '').html_safe
  else
    formatted_number
  end

end