Generates an exhaustive set of number combinations consisting of `e` positions in each combination and each number in the combination is a value 0 to `n`

set_generator.rb

# Generates an exhaustive set of number combinations
# consisting of `e` positions in each combination
# and each number in the combination is a value 0 to `n`
#
# - examples:
# 	set(2, 2)
# 	=> [[0, 0], [0, 1], [1, 0], [1, 1]]
#
# 	set(3, 3)
# 	=> [[0, 0, 0], [0, 0, 1], [0, 0, 2], [0, 1, 0], [0, 1, 1], [0, 1, 2], [0, 2, 0], [0, 2, 1], [0, 2, 2], [1, 0, 0], [1, 0, 1], [1, 0, 2], [1, 1, 0], [1, 1, 1], [1, 1, 2], [1, 2, 0], [1, 2, 1], [1, 2, 2], [2, 0, 0], [2, 0, 1], [2, 0, 2], [2, 1, 0], [2, 1, 1], [2, 1, 2], [2, 2, 0], [2, 2, 1], [2, 2, 2]]

def set(n, e)
	Array.new(n**e) do |i|
		a = []
		if e > 0
			j = e - 1
			while j >= 0
				a << i / n**j % n
				j -= 1
			end
		end
		a
	end
end

if __FILE__ == $0
	n = 6
	e = 4
	a = base(n, e)
	a.each {|i| puts i.join(' ')}
	puts "Combinations (#{n}, #{e}): #{a.length}"
end