Error: Cannot assign value of type '[String]' to type 'String' in swift

I am trying to create a search filter using a tableview with multiple sections and get the error 'Cannot assign value of type '[String]' to type 'String' on the line "cell?.textLabel?.text = self.searchArray[indexPath.row].rowTitles". How do I fix this? The ultimate goal is to be able to display the rowTitles in sections of the tableview. Here is my code.

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var searchBar: UISearchBar!
    @IBOutlet weak var tableView: UITableView!

    let dataArray = [(sectionTitle: "section 1", rowTitles: ["row 1", "row 2"]),
    (sectionTitle: "section 2", rowTitles: ["row 1", "row 2", "row 3"]),
    (sectionTitle: "section 3", rowTitles: ["row 1"]),
    ]
    var searchArray = [(sectionTitle: String, rowTitles: [String])]()
    var searching = false

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self
    }
}

extension ViewController: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if searching {
            return searchArray.count
        } else {
            return dataArray.count
        }
    }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "searchCell")
        if searching {
            cell?.textLabel?.text = self.searchArray[indexPath.row].rowTitles
        } else {
            cell?.textLabel?.text = self.dataArray[indexPath.row].rowTitles
        }
        return cell!
    }
    func numberOfSections(in tableView: UITableView) -> Int {
        return self.dataArray.count
    }
}


extension ViewController: UISearchBarDelegate {
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        searchArray =  dataArray.filter({$0.sectionTitle.lowercased().contains(searchBar.text!.lowercased())} )
        searching = true
        tableView.reloadData()
    }
}