Adding parameters to Array Product function in Ruby - arrays

Question

So I've been scratching my head trying to find a solution to this.
I need a method that will take any number of arrays that I need to collect the product of.
1 array:
return [A, B, C] # => [A, B, C]
2 arrays:
return [A, B, C].product([1, 2, 3]) # => [[A, 1], [A, 2], [A, 3], [B, 1] ... [C, 3]]
3 arrays:
return [A, B, C].product([1, 2, 3,],[x, y, z]) # => [[A, 1, x], [A, 1, y], ... [C, 3, z]]
So my current solution is this case switch, which is functional but inconvenient.
case options.count
when 1
options[0].values
when 2
options[0].values.product(options[1].values)
when 3
options[0].values.product(options[1].values,
options[2].values)
when 4
options[0].values.product(options[1].values,
options[2].values,
options[3].values)
end
What I'm looking for is a method that procedurally or recursively returns the product of an unknown number of arrays. The output needs to be like the above arrays.
I've tried:
array = options[0].values
options.each_with_index do |option, i|
array = array.product(option.values) if i > 0
end
return array
But it returns:
[[[A, 1], x], [[A, 1], y], [[A, 1], z], [[A, 2], x], ... [[C, 3], z]]
Which groups the values incorrectly.

Answer 1

How about something like:
def multi_product(base, *args)
base.product(*args)
end
results:
multi_product(['A', 'B', 'C'])
# => [["A"], ["B"], ["C"]]
multi_product(['A', 'B', 'C'], [1, 2, 3])
# => [["A", 1], ["A", 2], ["A", 3], ["B", 1], ["B", 2], ["B", 3], ["C", 1], ["C", 2], ["C", 3]]
multi_product(['A', 'B', 'C'], [1, 2, 3], ['x', 'y', 'z'])
# => [["A", 1, "x"], ["A", 1, "y"], ["A", 1, "z"], ["A", 2, "x"], ["A", 2, "y"], ["A", 2, "z"], ["A", 3, "x"], ["A", 3, "y"], ["A", 3, "z"], ["B", 1, "x"], ["B", 1, "y"], ["B", 1, "z"], ["B", 2, "x"], ["B", 2, "y"], ["B", 2, "z"], ["B", 3, "x"], ["B", 3, "y"], ["B", 3, "z"], ["C", 1, "x"], ["C", 1, "y"], ["C", 1, "z"], ["C", 2, "x"], ["C", 2, "y"], ["C", 2, "z"], ["C", 3, "x"], ["C", 3, "y"], ["C", 3, "z"]]
multi_product(['A', 'B', 'C'], [1, 2, 3], ['x', 'y', 'z'], [4, 5, 6])
# => [["A", 1, "x", 4], ["A", 1, "x", 5], ["A", 1, "x", 6], ["A", 1, "y", 4], ["A", 1, "y", 5], ["A", 1, "y", 6], ["A", 1, "z", 4], ["A", 1, "z", 5], ["A", 1, "z", 6], ["A", 2, "x", 4], ["A", 2, "x", 5], ["A", 2, "x", 6], ["A", 2, "y", 4], ["A", 2, "y", 5], ["A", 2, "y", 6], ["A", 2, "z", 4], ["A", 2, "z", 5], ["A", 2, "z", 6], ["A", 3, "x", 4], ["A", 3, "x", 5], ["A", 3, "x", 6], ["A", 3, "y", 4], ["A", 3, "y", 5], ["A", 3, "y", 6], ["A", 3, "z", 4], ["A", 3, "z", 5], ["A", 3, "z", 6], ["B", 1, "x", 4], ["B", 1, "x", 5], ["B", 1, "x", 6], ["B", 1, "y", 4], ["B", 1, "y", 5], ["B", 1, "y", 6], ["B", 1, "z", 4], ["B", 1, "z", 5], ["B", 1, "z", 6], ["B", 2, "x", 4], ["B", 2, "x", 5], ["B", 2, "x", 6], ["B", 2, "y", 4], ["B", 2, "y", 5], ["B", 2, "y", 6], ["B", 2, "z", 4], ["B", 2, "z", 5], ["B", 2, "z", 6], ["B", 3, "x", 4], ["B", 3, "x", 5], ["B", 3, "x", 6], ["B", 3, "y", 4], ["B", 3, "y", 5], ["B", 3, "y", 6], ["B", 3, "z", 4], ["B", 3, "z", 5], ["B", 3, "z", 6], ["C", 1, "x", 4], ["C", 1, "x", 5], ["C", 1, "x", 6], ["C", 1, "y", 4], ["C", 1, "y", 5], ["C", 1, "y", 6], ["C", 1, "z", 4], ["C", 1, "z", 5], ["C", 1, "z", 6], ["C", 2, "x", 4], ["C", 2, "x", 5], ["C", 2, "x", 6], ["C", 2, "y", 4], ["C", 2, "y", 5], ["C", 2, "y", 6], ["C", 2, "z", 4], ["C", 2, "z", 5], ["C", 2, "z", 6], ["C", 3, "x", 4], ["C", 3, "x", 5], ["C", 3, "x", 6], ["C", 3, "y", 4], ["C", 3, "y", 5], ["C", 3, "y", 6], ["C", 3, "z", 4], ["C", 3, "z", 5], ["C", 3, "z", 6]]
What it does is take one required parameter (base) which responds to product and then the *args takes a variable number of other parameters and stores them in an array args. You can then use * to deconstruct an array back into an argument list, which is done inside the call to product(*args) so that (in the case of the second example) ends up looking like
['A', 'B', 'C'].product([1, 2, 3], ['x', 'y', 'z'])

Answer 2

Hope this helps
a = [["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]]
a[0].product(*a[1..a.length])
#=> [["a", "d", "g"], ["a", "d", "h"], ["a", "d", "i"], ["a", "e", "g"], ["a", "e", "h"], ["a", "e", "i"], ["a", "f", "g"], ["a", "f", "h"], ["a", "f", "i"], ["b", "d", "g"], ["b", "d", "h"], ["b", "d", "i"], ["b", "e", "g"], ["b", "e", "h"], ["b", "e", "i"], ["b", "f", "g"], ["b", "f", "h"], ["b", "f", "i"], ["c", "d", "g"], ["c", "d", "h"], ["c", "d", "i"], ["c", "e", "g"], ["c", "e", "h"], ["c", "e", "i"], ["c", "f", "g"], ["c", "f", "h"], ["c", "f", "i"]]
# or
a.slice!(0).product(*a) #Note: this mutates array.
# or
a[0].product(*a.drop(1)) # suggested by Cary Swoveland