Combination of two arrays in Ruby

Question

What is the Ruby way to achieve following?

a = [1,2]
b = [3,4]

I want an array:

=> [f(1,3) ,f(1,4) , f(2,3) ,f(2,4)]
         


        

Answer 1

Facets has Array#product which will give you the cross product of arrays. It is also aliased as the ** operator for the two-array case. Using that, it would look like this:

require 'facets/array'
a = [1,2]
b = [3,4]

(a.product b).collect {|x, y| f(x, y)}

If you are using Ruby 1.9, product is a built-in Array function.