Class: Integer

Inherits:
Object show all
Includes:
Random::IntegerExtensions
Defined in:
lib/core/facets/roman.rb,
lib/core/facets/integer/of.rb,
lib/core/facets/integer/bitmask.rb,
lib/core/facets/integer/ordinal.rb,
lib/core/facets/integer/multiple.rb,
lib/core/facets/integer/factorial.rb,
lib/standard/facets/random.rb

Instance Method Summary collapse

Methods included from Random::IntegerExtensions

#random_delta

Instance Method Details

#bit(bit) ⇒ Object

Set a bit.

0.bit(4)  #=> 16

Using a negative figure will clear a bit.

10.bit(-4)      #=> 2

This is more easily seen using binary.

0b0100.bit(-3)  #=> 0

CREDIT: Thomas Sawyer, George Moschovitis


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# File 'lib/core/facets/integer/bitmask.rb', line 17

def bit(bit)
  if bit < 0
    mask = (1 << ~bit)
    self & ~mask
  else
    mask = (1 << bit)
    self | mask
  end
end

#bit?(bit) ⇒ Boolean

Is a bit set?

8.bit?(3)  #=> true
8.bit?(2)  #=> false

CREDIT: Thomas Sawyer, George Moschovitis

Returns:

  • (Boolean)

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# File 'lib/core/facets/integer/bitmask.rb', line 43

def bit?(bit)
  mask = (1 << bit)
  (self & mask) != 0
end

#bit_clear(bit) ⇒ Object

Clear bit.

CREDIT: George Moschovitis


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# File 'lib/core/facets/integer/bitmask.rb', line 31

def bit_clear(bit)
  mask = (1 << bit)
  self & ~mask
end

#bitmask(mask) ⇒ Object

Apply a bitmask.

1.bitmask(6) #=> 7

Using a inverted bitmask clears bits.

7.bitmask(~2) #=> 5
5.bitmask(~2) #=> 5

CREDIT: George Moschovitis


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# File 'lib/core/facets/integer/bitmask.rb', line 59

def bitmask(mask)
  if mask < 0
    self & mask
  else
    self | mask
  end
end

#bitmask?(mask) ⇒ Boolean

Is bitmask set?

7.bitmask?(7) #=> true
7.bitmask?(5) #=> true
8.bitmask?(3) #=> false

CREDIT: George Moschovitis

Returns:

  • (Boolean)

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# File 'lib/core/facets/integer/bitmask.rb', line 75

def bitmask?(mask)
  (self & mask) != 0
end

#factorialObject Also known as: fac

Calculate the factorial of an integer.

2.factorial  #=> 2
3.factorial  #=> 6
4.factorial  #=> 24

CREDIT: Malte Milatz


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# File 'lib/core/facets/integer/factorial.rb', line 11

def factorial
  return 1 if zero?
  f = 1
  2.upto(self) { |n| f *= n }
  f
end

#multiple?(number) ⇒ Boolean

Is self a multiple of a given number?

7.multiple?(2)  #=> false
8.multiple?(2)  #=> true

CREDIT: Trans

Returns:

  • (Boolean)

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# File 'lib/core/facets/integer/multiple.rb', line 10

def multiple?(number)
  if number.zero?
    zero? ? true : false
  else
    self % number == 0
  end
end

#of(&block) ⇒ Object Also known as: times_collect, times_map

Like #times but returns a collection of the yield results.

a = 3.of { |i| "#{i+1}" }
a #=> [ "1", "2", "3" ]

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# File 'lib/core/facets/integer/of.rb', line 9

def of(&block)
  Array.new(self, &block)
end

#ordinalObject Also known as: ordinalize


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# File 'lib/core/facets/integer/ordinal.rb', line 3

def ordinal
  if [11,12,13].include?(self % 100)
    "#{self}th"
  else
    case (self % 10)
    when 1
      "#{self}st"
    when 2
      "#{self}nd"
    when 3
      "#{self}rd"
    else
      "#{self}th"
    end
  end
end

#romanObject

Converts this integer to a roman numeral.

NOTE: This method is not a common core extension and is not loaded automatically when using require 'facets'.

Uncommon:

  • require 'facets/integer/roman'


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# File 'lib/core/facets/roman.rb', line 31

def roman
  int = self  #return nil if integer > ROMAN_MAX

  return "-#{(-int).roman}" if int < 0
  return "" if int == 0
  ROMAN_VALUES.each do |(i, v)|
    return(i + (int-v).roman) if v <= int 
  end
end