How to check and delete duplicates values in TableView? - ios

Question

I have a database on Firebase and a tableview.
I have a list of brands, models, and year for motorcycles and I want to retrieve the list of brands on the tableview.
The problem is the DB has duplicates values. There is more than one motorcycle from Suzuki, there is more one models of SV 650, etc.
How can I check duplicates values, put it in a new array, and retrieve it in the tableview?
This is my TableViewController file:
import UIKit
import FirebaseAuth
import FirebaseDatabase
class SelectionMarqueViewController: UITableViewController {
var posts = [Post]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = self
loadMarques()
}
func loadMarques() {
var ref : DatabaseReference?
ref = Database.database(url: "https://myride-test.firebaseio.com/").reference()
ref?.observe(.childAdded, with: { (snapshot) in
if let dict = snapshot.value as? [String: Any] {
let MarqueText = dict["Marque"] as! String
let post = Post(MarqueText: MarqueText)
self.posts.append(post)
print(self.posts)
self.tableView.reloadData()
}
})
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return posts.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "PostCell", for: indexPath)
cell.textLabel?.text = posts[indexPath.row].Marque
return cell
}
}
And this one is the file with the Post func:
import Foundation
class Post {
var Marque: String
init(MarqueText: String) {
Marque = MarqueText
}
}
Here my Firebase Database:
Actually the tableview shows the complete list of brands in the DB, and so, many times the same brands.
On the DB and code:
"Marque" correspond to the brand.

Answer 1

You can implement Hashable
class Post : Hashable {
var marque: String
init(marqueText: String) {
marque = marqueText
}
// Equatable for contains
static func == (lhs:Post,rhs:Post) -> Bool {
return lhs.marque == rhs.marque
}
// Hashable for Set
var hashValue:Int {
return marque.hashValue
}
}
and use
if let dict = snapshot.value as? [String: Any] {
let MarqueText = dict["Marque"] as! String
let post = Post(MarqueText: MarqueText)
self.posts.append(post)
self.posts = Array(Set(self.posts))
print(self.posts)
self.tableView.reloadData()
}
Or simply
let marqueText = dict["Marque"] as! String
if !self.posts.map { $0.marqueText}.contains(marqueText) {
let post = Post(marqueText:marqueText)
self.posts.append(post)
self.tableView.reloadData()
}

Answer 2

Check and append if the marque is not available in the datasource of the tableview.
func appendMarqueAndReloadIfNeeded(_ marque: String) {
if self.posts.map({ $0.Marque }).contains(marque) {
// Do nothing
} else {
self.posts.append(Post(MarqueText: marque))
self.tableView.reloadData()
}
}
Then you call it inside observe:
///....
if let dict = snapshot.value as? [String: Any] {
let MarqueText = dict["Marque"] as! String
self.appendMarqueAndReloadIfNeeded(MarqueText)
}
///....