Rubyist Test - Task 1

Task1.rb

class Array
	def new_inject total=0
		# self.each do |i|
		# 	total = yield(total, i)
		# end
		for i in (0...self.length)
			total = yield(total, self[i])
		end
		total
	end

	# # Neatest
	# def recursive_inject total=0,array=self.dup,&block
	# 	array.empty? ? total : recursive_inject(yield(total, array.shift),array,&block)
	# end

	# More readable, I guess...
	def recursive_inject(total=0, array=self.dup, &block)
		return total if array.empty?
		new_total = yield(total, array.shift)
		recursive_inject(new_total, array, &block)
	end
end


describe Array do
	context "(only dealing with situations where a block is given)" do
		it "should be able to add up all the numbers in an array" do
			array = [1,2,3,4]
			ans = array.new_inject { |memo, i| memo += i }
			expect(ans).to eq(10)
		end

		it "should be able to add up all the numbers in an array with an initial value" do
			array = [1,2,3,4]
			ans = array.new_inject(5) { |memo, i| memo += i }
			expect(ans).to eq(15)
		end

		it "should be able to create new arrays" do
			array = [1,2,3,4]
			ans = array.new_inject([]) { |memo, i| i.even? ? memo << i : memo }
			expect(ans).to eq([2,4])
		end
	end

	context "(doing the same thing recursively)" do
		it "should be able to add up all the numbers in an array" do
			array = [1,2,3,4]
			ans = array.recursive_inject { |memo, i| memo += i }
			expect(ans).to eq(10)
		end

		it "should be able to add up all the numbers in an array with an initial value" do
			array = [1,2,3,4]
			ans = array.recursive_inject(5) { |memo, i| memo += i }
			expect(ans).to eq(15)
		end

		it "should be able to create new arrays" do
			array = [1,2,3,4]
			ans = array.recursive_inject([]) { |memo, i| i.even? ? memo << i : memo }
			expect(ans).to eq([2,4])
		end
	end
end