Track Mode : Utility Method « Method « Ruby

1. Ruby
2. Method
3. Utility Method

Track Mode

def modes(array, find_all=true)
  histogram = array.inject(Hash.new(0)) { |h, n| h[n] += 1; h }
  modes = nil
  histogram.each_pair do |item, times|
    modes << item if modes && times == modes[0] and find_all
    modes = [times, item] if (!modes && times>1) or (modes && times>modes[0])
  end
  return modes ? modes[1...modes.size] : modes
end

puts modes([1,2,3,4])                                # => nil
puts modes([1,1,2,3,4])                              # => [1]
puts modes([1,1,2,2,3,4])                            # => [1, 2]
puts modes([1,1,2,2,3,4,4])                          # => [1, 2, 4]
puts modes([1,1,2,2,3,4,4], false)                   # => [1]
puts modes([1,1,2,2,3,4,4,4,4,4])                    # => [4]

 

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