Viewcontroller.swift

class ViewController: UIViewController {

    @IBOutlet weak var tableview: UITableView!
    @IBOutlet weak var segmentedControl: UISegmentedControl!
    
    var followers = [String]()
     var following = [String]()
    
    var tableData = [String]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        for i in 1...10000 {
            following.append("Following \(i)")
            followers.append("Follower \(i)")
        }
        self.tableData = followers
        self.segmentedControl.selectedSegmentIndex = 0
        // Do any additional setup after loading the view.
    }
    
    @IBAction func segmentChanged(_ sender: UISegmentedControl) {
        switch sender.selectedSegmentIndex {
        case 0:
            self.tableData = followers
        case 1:
            self.tableData = following
        default:
            return
        }
        self.tableview.reloadData()
    }


}

extension ViewController: UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return tableData.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        cell.textLabel?.text = self.tableData[indexPath.row]
        return cell
    }
}