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

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Mechanical Engineering
                            [slug] => mechanical-engineering
                            [id] => 1881
                        )

                )

        )

    [1760] => Array
        (
            [parent_category_id] => 1760
            [parent_category] => Array
                (
                    [id] => 1760
                    [slug] => english-reading
                    [name] => English and Reading
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Literature
                            [slug] => literature
                            [id] => 1766
                        )

                    [1] => Array
                        (
                            [name] => Proofreading
                            [slug] => proofreading
                            [id] => 1767
                        )

                    [2] => Array
                        (
                            [name] => Reading
                            [slug] => reading
                            [id] => 1763
                        )

                    [3] => Array
                        (
                            [name] => Vocabulary
                            [slug] => vocabulary
                            [id] => 1765
                        )

                    [4] => Array
                        (
                            [name] => Writing
                            [slug] => writing
                            [id] => 1764
                        )

                )

        )

    [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
                        )

                    [2] => Array
                        (
                            [name] => Physical Science
                            [slug] => physical-science
                            [id] => 1745
                        )

                    [3] => Array
                        (
                            [name] => Physics
                            [slug] => physics
                            [id] => 1748
                        )

                )

        )

)