Class: Benford

Inherits:
Object
  • Object
show all
Defined in:
lib/benford.rb

Instance Method Summary collapse

Instance Method Details

#counts ⇒ Object 



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# File 'lib/benford.rb', line 20

def counts
  return @digit_counts unless @digit_counts.nil?
  digit_counts = Hash.new(0)
  numbers.each do |v|
    digit_counts[v.first] += 1
  end
  @digit_counts = digit_counts
end

#deviation ⇒ Object 



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# File 'lib/benford.rb', line 42

def deviation
  return @variants unless @variants.nil?
  variants = Hash.new(0.0)
  law.each do |digit, occurence|
    variants[digit] = distribution[digit] - occurence
  end
  @variants = variants
end

#distribution ⇒ Object 



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# File 'lib/benford.rb', line 29

def distribution
  return @dist unless @dist.nil?
  dist = Hash.new(0.0)
  counts.each do |k, v|
    dist[k] = v.to_f / numbers.count
  end
  @dist = dist
end

#law ⇒ Object

P(d) = log10(1 + 1/d)



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# File 'lib/benford.rb', line 13

def law
  return @benford unless @benford.nil?
  benford = {}
  (1..9).each { |d| benford[d.to_s] = Math.log10( 1 + 1 / d.to_f) }
  @benford = benford
end

#load!(nums) ⇒ Object 



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# File 'lib/benford.rb', line 3

def load!(nums)
  @numbers = []
  nums.each do |num|
    num.gsub!(".", "")
    num.gsub!(",", "")
    @numbers << num.to_s if num.is_numeric?
  end
end

#numbers ⇒ Object 



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# File 'lib/benford.rb', line 38

def numbers 
  @numbers
end