Convert string into Array in rails

require 'json'

JSON.parse "[1,2,3,4,5]"
  #=> [1, 2, 3, 4, 5] 

JSON.parse "[[1,2],3,4]"
  #=> [[1, 2], 3, 4] 

Perhaps this?

   s.tr('[]', '').split(',').map(&:to_i)