Output variable in multi dimension array

I have a form that spits out an array with the code - print_r($result);

This outputs the following:

Array
(
    [0] => stdClass Object
        (
            [input_index] => 0
            [candidate_index] => 0
            [delivery_line_1] => 5259 N Elderberry Ct SE
            [last_line] => Kentwood MI 49512-9693
            [delivery_point_barcode] => 495129693598
            [components] => stdClass Object
                (
                    [primary_number] => 5259
                    [street_predirection] => N
                    [street_name] => Elderberry
                    [street_postdirection] => SE
                    [street_suffix] => Ct
                    [city_name] => Kentwood
                    [state_abbreviation] => MI
                    [zipcode] => 49512
                    [plus4_code] => 9693
                    [delivery_point] => 59
                    [delivery_point_check_digit] => 8
                )

            [metadata] => stdClass Object
                (
                    [record_type] => S
                    [county_fips] => 26081
                    [county_name] => Kent
                    [carrier_route] => R087
                    [congressional_district] => 02
                    [rdi] => Residential
                    [latitude] => 42.868
                    [longitude] => -85.57536
                    [precision] => Zip9
                )

            [analysis] => stdClass Object
                (
                    [dpv_match_code] => Y
                    [dpv_footnotes] => AABB
                    [dpv_cmra] => N
                    [dpv_vacant] => N
                    [active] => Y
                    [footnotes] => N#
                )

        )

)

I need to assign the [rdi] value to a variable. How do I access that spot in the array with PHP?

Thanks