如何在swift 3 tableview中过滤多维数组

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UISearchBarDelegate {

    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var searchBar: UISearchBar!
    
    var data = [[String]]()
    var filteredData = [[String]]()
    var isSearching = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 初始化数据
        data = [["Apple", "iPhone", "iPad"], ["Google", "Pixel", "Nexus"], ["Samsung", "Galaxy", "Note"]]
        
        // 设置TableView的数据源和代理
        tableView.dataSource = self
        
        // 设置SearchBar的代理
        searchBar.delegate = self
    }
    
    // MARK: - TableView DataSource
    
    func numberOfSections(in tableView: UITableView) -> Int {
        if isSearching {
            return filteredData.count
        } else {
            return data.count
        }
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if isSearching {
            return filteredData[section].count
        } else {
            return data[section].count
        }
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        
        if isSearching {
            cell.textLabel?.text = filteredData[indexPath.section][indexPath.row]
        } else {
            cell.textLabel?.text = data[indexPath.section][indexPath.row]
        }
        
        return cell
    }
    
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        if isSearching {
            return "Filtered Data"
        } else {
            return "Data"
        }
    }
    
    // MARK: - SearchBar Delegate
    
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if searchText.isEmpty {
            isSearching = false
            tableView.reloadData()
        } else {
            isSearching = true
            filteredData = data.map { $0.filter { $0.lowercased().contains(searchText.lowercased()) } }
            tableView.reloadData()
        }
    }
}