Fixnum#power_of?

gistfile1.rb

class Fixnum
  def power_of?(i)
    self != 0 and Math.log(self.abs, i) % 1 == 0
  end
end

puts 8.power_of? 2     # => true
puts 64.power_of? 2    # => true
puts 27.power_of? 3    # => true
puts 27.power_of? 4    # => false
puts 128.power_of? 4   # => false
puts 256.power_of? 4   # => true