Sort array from CoreData Identity

Question

I'm trying to sort an array. Inside the array are naamdeelnemer, totaalpunten etc. When I print for a check the array returns [ ]. Anyone who can help me?

import UIKit
import CoreData



var userArray:[Punten] = []

override func viewDidLoad() {

    super.viewDidLoad()

    userArray.sort { $0.naamdeelnemer! < $1.naamdeelnemer!}
    print(userArray)

    tableView.delegate = self
    tableView.dataSource = self

    self.fetchData()
    self.tableView.reloadData()
}

override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return userArray.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
    let name = userArray[indexPath.row]

    cell.textLabel!.text = name.naamdeelnemer! + "    " + String(name.totaalpunten)


    return cell
}

func fetchData() {

    let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

    do {
        userArray = try context.fetch(Punten.fetchRequest())
    }
    catch {
        print(error)

    }
}

You do the sort BEFORE you fetch the content. Also, you can use a NSSortDescriptor on your request. — Larme
– Larme, Commented Feb 27, 2018 at 13:06

iOS · Accepted Answer · 2018-02-27 13:14:00Z

1

You can use "NSSortDescriptor" on the request while fetching the data from Core Data. Please find sample code below:

let request = NSFetchRequest<NSFetchRequestResult>(entityName: "TableName")
request.sortDescriptors = [NSSortDescriptor(key: "naamdeelnemer", ascending: true)]

Here, "TableName" is the name of table to fetch record. "naamdeelnemer" is the field on which the sorting can be done. ascending: parameter can be "true" or "false"

answered Feb 27, 2018 at 13:14

iOS

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Comments

vadian · Accepted Answer · 2018-02-27 15:43:03Z

0

You have first to fetch the data then sort them

self.fetchData()
userArray.sort { $0.naamdeelnemer! < $1.naamdeelnemer!}

However this is not CoreData like. Fetch the data passing a sort descriptor. This is much more efficient

func fetchData() {

    let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
    let request : NSFetchRequest<Punten> = Punten.fetchRequest()
    request.sortDescriptors = [NSSortDescriptor(key: "naamdeelnemer", ascending: true)]

    do {
        userArray = try context.fetch(request)
    }
    catch {
        print(error)

    }
}

and

~~userArray.sort { $0.naamdeelnemer! < $1.naamdeelnemer!}~~

edited Feb 27, 2018 at 15:43

answered Feb 27, 2018 at 13:09

vadian

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2 Comments

Ed Wisseborn Over a year ago

I get this: Ambiguous use of 'fetchRequest()'

vadian Over a year ago

My bad, I uodated the answer.

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