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Contents
module CorrectHorseBatteryStaple
class StatisticalArray
def initialize(array, sorted=false)
@obj = array
@sorted = sorted
end
def self.cast(array, sorted=false)
if array.is_a?(CorrectHorseBatteryStaple::StatisticalArray)
array
else
CorrectHorseBatteryStaple::StatisticalArray.new(array, sorted)
end
end
def sort!
@obj = @obj.sort unless @sorted
@sorted = true
self
end
def sort_by!(&block)
@obj = @obj.sort_by(&block)
@sorted = true
self
end
def method_missing(name, *args, &block)
@obj.__send__(name, *args, &block)
end
def mean
inject(0) { |sum, x| sum += x } / size.to_f
end
alias :average :mean
def sum
reduce(:+)
end
def sort(&block)
return super(&block) if block || !@sorted
self
end
def standard_deviation(m = mean)
variance = inject(0) { |v, x| v += (x - m) ** 2 }
return Math.sqrt(variance/(size-1))
end
def mean_and_standard_deviation
return m=mean, standard_deviation(m)
end
def percentile_index(percentile, round=true)
r = percentile.to_f/100 * length + 0.5
round ? r.round : r
end
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
def select_percentile(range)
slice(index_range_for_percentile(range))
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems