reloadData test

//

class TestTableViewController: UITableViewController {

    var myData: [Int] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        // fill myData with 1000, 1100, 1200, 1300, 1400
        myData = (0..<5).map { 1000 + ($0 * 100)  }

        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "c")
    }
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return myData.count
    }
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // output the row and the data for that row
        print("r:\t", indexPath.row, "\t", myData[indexPath.row], "\tin cellForRowAt")

        let c = tableView.dequeueReusableCell(withIdentifier: "c", for: indexPath)
        c.textLabel?.text = "\(myData[indexPath.row])"
        return c
    }
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        self.myReload()
    }

    func myReload() {

        print()
        print("on entry to myReload(), myData is")
        print()

        // output the updated data
        print(myData)

        print()
        print("now call .reloadData()")

        // call .reloadData here
        tableView.reloadData()

        print()
        print("now modify data")
        print()

        for i in 0..<myData.count {
            myData[i] = myData[i] + 10
        }

        print("myData is now")
        print()

        // output the updated data
        print(myData)

        print()
        print("which is shown in the table, even though we updated the data *after* calling .reloadData()")
        print()

    }

}

// output is:

/*

r:   0   1000   in cellForRowAt
r:   1   1100   in cellForRowAt
r:   2   1200   in cellForRowAt
r:   3   1300   in cellForRowAt
r:   4   1400   in cellForRowAt

on entry to myReload(), myData is

[1000, 1100, 1200, 1300, 1400]

now call .reloadData()

now modify data

myData is now

[1010, 1110, 1210, 1310, 1410]

which is shown in the table, even though we updated the data *after* calling .reloadData()

r:   0   1010   in cellForRowAt
r:   1   1110   in cellForRowAt
r:   2   1210   in cellForRowAt
r:   3   1310   in cellForRowAt
r:   4   1410   in cellForRowAt

*/