Class: CorrectHorseBatteryStaple::StatisticalArray

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

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(array, sorted = false) ⇒ StatisticalArray

Returns a new instance of StatisticalArray.



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 4

def initialize(array, sorted=false)
  @obj    = array
  @sorted = sorted
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 29

def method_missing(name, *args, &block)
  @obj.__send__(name, *args, &block)
end

Class Method Details

.cast(array, sorted = false) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 9

def self.cast(array, sorted=false)
  if array.is_a?(CorrectHorseBatteryStaple::StatisticalArray)
    array
  else
    CorrectHorseBatteryStaple::StatisticalArray.new(array, sorted)
  end
end

Instance Method Details

#index_range_for_percentile(range) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 61

def index_range_for_percentile(range)
  range = Range.new(range - 0.5, range + 0.5) if range.is_a?(Numeric)
  sort!

  (percentile_index(range.begin, false).floor ..
      percentile_index(range.end,   false).ceil)
end

#mean ⇒ Object Also known as: average 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 33

def mean
  inject(0) { |sum, x| sum += x } / size.to_f
end

#mean_and_standard_deviation ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 52

def mean_and_standard_deviation
  return m=mean, standard_deviation(m)
end

#percentile_index(percentile, round = true) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 56

def percentile_index(percentile, round=true)
  r = percentile.to_f/100 * length + 0.5
  round ? r.round : r
end

#select_percentile(range) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 69

def select_percentile(range)
  slice(index_range_for_percentile(range))
end

#sort(&block) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 42

def sort(&block)
  return super(&block) if block || !@sorted
  self
end

#sort! ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 17

def sort!
  @obj    = @obj.sort unless @sorted
  @sorted = true
  self
end

#sort_by!(&block) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 23

def sort_by!(&block)
  @obj     = @obj.sort_by(&block)
  @sorted  = true
  self
end

#standard_deviation(m = mean) ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 47

def standard_deviation(m = mean)
  variance = inject(0) { |v, x| v += (x - m) ** 2 }
  return Math.sqrt(variance/(size-1))
end

#sum ⇒ Object 



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# File 'lib/correct_horse_battery_staple/statistical_array.rb', line 38

def sum
  reduce(:+)
end