Question

In order to compute the cartesian product in Ruby, one can use Array#product, how is the syntax if I have an array of arrays and want to compute the product?

[[1,2],[3,4],[5,6]] => [[1,3,5], [2,3,5], ...]

I am not sure, because in the Ruby documentation the product method is defined with an arbitrary number of arguments, so simply passing my arrays of arrays as an argument, like that:

[].product(as) => [

does not suffice. How can I solve this?

Answer 1

The method takes multiple arguments, but not an array containing arguments. So you have to use it in this way:

[1,2].product [3,4], [5,6]

If as is your array of arrays, you will have to “splat” it like this:

as[0].product(*as[1..-1])