Combine array of array into all possible combinations, forward only, in Ruby

Question

I have an array of arrays, like so:

[[\'1\',\'2\'],[\'a\',\'b\'],[\'x\',\'y\']]

I need to combine those arrays into a string containing all

Answer 1

Know your Array#product:

a = [['1','2'],['a','b'],['x','y']]
a.first.product(*a[1..-1]).map(&:join)