Array
(
    [1880] => Array
        (
            [parent_category_id] => 1880
            [parent_category] => Array
                (
                    [id] => 1880
                    [slug] => engineering
                    [name] => Engineering
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Chemical Engineering
                            [slug] => chemical-engineering
                            [id] => 1884
                        )

                )

        )

    [1723] => Array
        (
            [parent_category_id] => 1723
            [parent_category] => Array
                (
                    [id] => 1723
                    [slug] => math
                    [name] => Math
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Calculus
                            [slug] => calculus
                            [id] => 1730
                        )

                    [1] => Array
                        (
                            [name] => Precalculus
                            [slug] => precalculus
                            [id] => 1728
                        )

                )

        )

    [1744] => Array
        (
            [parent_category_id] => 1744
            [parent_category] => Array
                (
                    [id] => 1744
                    [slug] => science
                    [name] => Science
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Chemistry
                            [slug] => chemistry
                            [id] => 1747
                        )

                    [1] => Array
                        (
                            [name] => Organic Chemistry
                            [slug] => organic-chemistry
                            [id] => 1754
                        )

                )

        )

)