Sorting an array of arrays in Ruby

Question

I have an array of arrays like so:

irb(main):028:0> device_array
=> [[\"name1\", \"type1\", [\"A\", \"N\", \"N\"], [\"Attribute\", \"device_attribute\"], 9         


        

Answer 1

The 4th element is actually at index 3, which means you would do it like this:

all_devices.sort do |a, b|
  a[3] <=> b[3]
end

If you really want to sort the elements at index 4 (which doesn't exist for the first element of all_devices), then you need to add comparison to the NilClass first:

class NilClass
  def <=> (other)
    1
  end
end

all_devices.sort do |a, b|
  a[4] <=> b[4]
end

This will sort nil to the end. Change the return value of <=> to -1 to sort them to the front.