# hacks, candy, overrides, etc

class Hash
  # Usage { :a => 1, :b => 2, :c => 3}.except(:a) -> { :b => 2, :c => 3}
  def except(*keys)
    self.reject { |k,v|
      keys.include? k.to_sym
    }
  end

  # Usage { :a => 1, :b => 2, :c => 3}.only(:a) -> {:a => 1}
  def only(*keys)
    self.dup.reject { |k,v|
      !keys.include? k.to_sym
    }
  end
end


class Array
	# split an array based on block
	# ex:
	# strings, non_strings = [5,6,"aaa", 7, "ccc"].divorce { |element| element.is_a? String }
	# => [ ["aaa", "ccc"], [5,6,7] ]
	def divorce
		mom = []
		dad = []
		for i in 0...size
			value = self[i]
			if yield(value)
				mom << value
			else
				dad << value
			end
		end
		return [mom, dad]
	end

	def group_array_by(attribute = nil)
    arrays = {}
    for i in 0...size
      object = self[i]
      value = attribute ? object.send(attribute.to_sym) : yield(object)
      if arrays[value.to_s]
        arrays[value.to_s] << object
      else
        arrays[value.to_s] = [object]
      end
    end
    return arrays.values
  end
	
	def sum
		self.inject { |n,m| n += m }
	end
end

class String
	# replace parts of a string based on a hash
	# ex:
	# replace_hash = { "car" => "bike", "potato chips" => "apples", "store" => "fruit stand" }
	# my_string = "I'm going to take my car to the store and buy potato chips."
	# my_string.gsub_from_hash(replace_hash)
	# => "I'm going to take my bike to the fruit stand and buy apples."
	def gsub_from_hash(somehash = {})
		temp = self
		for part in somehash
			unless part[0].nil? or part[1].nil?
				temp = temp.gsub(part[0], part[1])
			end
		end
		temp
	end
	
	def unspace()
		self.gsub(" ", "_")
	end
end