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Contents
#--
# Credit goes to Brian Schröder for current code
# and Derek for original.
#++
module Enumerable
# Generates a hash mapping each unique symbol in the array
# to the relative frequency, i.e. the probablity, of
# it appearence.
def probability
probs = Hash.new(0.0)
size = 0.0
each do | e |
probs[e] += 1.0
size += 1.0
end
probs.keys.each { |e| probs[e] /= size }
probs
end
# old def
#
# def probability
# arr = self.to_a
# probHash = Hash.new
# size = arr.size.to_f
# arr.uniq.each do |i|
# ct = arr.inject(0) do |mem,obj|
# obj.eql?(i) ? (mem+1) : mem
# end
# probHash[i] = ct.to_f/size
# end
# probHash
# end
end
# _____ _
# |_ _|__ ___| |_
# | |/ _ \/ __| __|
# | | __/\__ \ |_
# |_|\___||___/\__|
#
=begin test
require 'test/unit'
class TCEnumerable < Test::Unit::TestCase
def test_probability
assert_equal( {'a'=>0.5,'b'=>0.5}, %w{a b}.probability )
assert_equal( {'tom'=>0.5,'boy'=>0.5}, %w{tom boy}.probability )
end
end
=end
Version data entries
26 entries across 26 versions & 1 rubygems