How we can sort(ascending and descending) a uitableview data in swift language

Well, just like it sounds - you'd filter the list:

func filterList() { // should probably be called sort and not filter
    fruitArr.sorted() { $0.fruitName > $1.fruitName } // sort the fruit by name
    fruitList.reloadData(); // notify the table view the data has changed
}

If you just want to reverse the items rather than actually sort them (to toggle the order) you can perform a fruitArr.reverse() instead of sorting.

Swift 3+

you can use .sorted() and .lowercased() (with string properties) to sort a-z, by default .sorted and .sort sort by A-z.

    //Prints Names A-z (0-9 then A-Z then a-z)
    fruitArr.sorted() { $0.fruitName > $1.fruitName }
    //prints  '000', 'Watermelon', 'apple'

    //Prints Name in alphabetical order.
    fruitArr.sorted() { $0.fruitName.lowercased() > $1.fruitName.lowercased() }
    //prints '000', 'apple', 'Watermelon'

See documentation for .sorted()