Module: SleepingKingStudios::Tools::IntegerTools

Extended by:
IntegerTools
Included in:
IntegerTools
Defined in:
lib/sleeping_king_studios/tools/integer_tools.rb

Overview

Tools for working with integers.

Constant Summary collapse

ROMANIZE_MIN =

Minimum integer value that can be converted to a roman numeral.

1
ROMANIZE_MAX =

Maximum integer value that can be converted to a roman numeral.

4999

Instance Method Summary collapse

Instance Method Details

#count_digits(integer, base: 10) ⇒ Integer

Returns the number of digits in the given integer when represented in the specified base. Ignores minus sign for negative numbers.

Examples:

With a positive number.

IntegerTools.count_digits(31)
#=> 2

With a negative number.

IntegerTools.count_digits(-141)
#=> 3

With a binary number.

IntegerTools.count_digits(189, :base => 2)
#=> 8

With a hexadecimal number.

IntegerTools.count_digits(16724838, :base => 16)
#=> 6

Parameters:

  • integer (Integer) —

    The integer to analyze.

  • base (Integer) (defaults to: 10) —

    The numeric base to represent the integer in. Defaults to 10.

Returns:

  • (Integer) —

    The number of digits.



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# File 'lib/sleeping_king_studios/tools/integer_tools.rb', line 40

def count_digits integer, base: 10
  digits(integer.abs, :base => base).count
end

#digits(integer, base: 10) ⇒ Array<String>

Decomposes the given integer into its digits when represented in the given base.

Examples:

With a number in base 10.

IntegerTools.digits(15926)
#=> ['1', '5', '9', '2', '6']

With a binary number.

IntegerTools.digits(189, :base => 2)
#=> ['1', '0', '1', '1', '1', '1', '0', '1']

With a hexadecimal number.

IntegerTools.digits(16724838)
#=> ['f', 'f', '3', '3', '6', '6']

Parameters:

  • integer (Integer) —

    The integer to decompose.

  • base (Integer) (defaults to: 10) —

    The numeric base to represent the integer in. Defaults to 10.

Returns:

  • (Array<String>) —

    The digits of the decomposed integer, represented as a bigendian array of strings.



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# File 'lib/sleeping_king_studios/tools/integer_tools.rb', line 65

def digits integer, base: 10
  integer.to_s(base).split('')
end

#integer?(int) ⇒ Boolean

Returns true if the object is an Integer.

Parameters:

  • int (Object) —

    The object to test.

Returns:

  • (Boolean) —

    True if the object is an Integer, otherwise false.



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# File 'lib/sleeping_king_studios/tools/integer_tools.rb', line 74

def integer? int
  Integer === int
end

#pluralize(count, single, plural) ⇒ String

Returns the singular or the plural value, depending on the provided item count.

Examples:

"There are four #{StringTools.pluralize 4, 'light', 'lights'}!"
#=> 'There are four lights!'

Parameters:

  • count (Integer) —

    The number of items.

  • single (String) —

    The singular form of the word or phrase.

  • plural (String) —

    The plural form of the word or phrase.

Returns:

  • (String) —

    The single form if count == 1; otherwise the plural form.



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# File 'lib/sleeping_king_studios/tools/integer_tools.rb', line 91

def pluralize count, single, plural
  1 == count ? single : plural
end

#romanize(integer, additive: false) ⇒ String

Represents an integer between 1 and 4999 (inclusive) as a Roman numeral.

Examples:

IntegerTools.romanize(4) #=> 'IV'

IntegerTools.romanize(18) #=> 'XVIII'

IntegerTools.romanize(499) #=> 'CDXCIX'

Parameters:

  • integer (Integer) —

    The integer to convert.

  • additive (Boolean) (defaults to: false) —

    If true, then uses only additive Roman numerals (e.g. four will be converted to IIII instead of IV, and nine will be converted to VIIII instead of IX). Defaults to false.

Returns:

  • (String) —

    The representation of the integer as a Roman numeral.

Raises:

  • (RangeError) —

    If the integer is less than 1 or greater than 4999.



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# File 'lib/sleeping_king_studios/tools/integer_tools.rb', line 114

def romanize integer, additive: false
  # Validate input value.
  unless (ROMANIZE_MIN..ROMANIZE_MAX).include? integer
    raise RangeError.new "integer to romanize must be within range #{ROMANIZE_MIN} to #{ROMANIZE_MAX}"
  end # unless

  # Define conversion rules.
  rules = [
    '',
    '%one',
    '%one%one',
    '%one%one%one',
    additive ? '%one%one%one%one' : '%one%five',
    '%five',
    '%five%one',
    '%five%one%one',
    '%five%one%one%one',
    additive ? '%five%one%one%one%one' : '%one%ten',
    '%ten'
  ] # end array

  # Define numeral values.
  numerals = [
    %w(I V X),
    %w(X L C),
    %w(C D M),
    ['M', 'MMM', '']
  ] # end array numerals

  # Generate string representation.
  digits(integer).reverse.map.with_index do |digit, index|
    rules[digit.to_i]
      .gsub('%one',  numerals[index][0])
      .gsub('%five', numerals[index][1])
      .gsub('%ten',  numerals[index][2])
  end.reverse.join ''
end