How can I implement an array filter with Swift?

Question

I'm parsing JSON with Alamofire and SwiftyJSON. TableView Controller is working absolutely fine but I need do eliminate/filter some of the objects. Like if an object in array of dictionary with an 'id', i.e. '1', persists, it should be filtered.

This is how JSON data looks like:

[
{
    "id": 1,
    "title": "item1",
    "created_at": "2014-08-30T15:50:38.421Z",
    "updated_at": "2014-08-30T15:50:38.421Z"
},
{
    "id": 2,
    "title": "item2",
    "created_at": "2014-08-30T15:50:38.453Z",
    "updated_at": "2014-08-30T15:50:38.453Z"
},
{
    "id": 3,
    "title": "item3",
    "created_at": "2014-08-30T15:50:38.464Z",
    "updated_at": "2014-08-30T15:50:38.464Z"
},
]

this is how table view controller looks like:

import UIKit
import Alamofire

class ViewController: UITableViewController {

    var items: Array<Item>?
    var username: JSON!
    var id: JSON!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        items = Array()

        Alamofire.request(.GET, "http://brownbro-json-api-test.herokuapp.com/api/items")
            .responseJSON {(request, response, JSONresponse, error) in
                let result = JSON(JSONresponse!)

                for (var i = 0; i < result.arrayValue.count; i++) {
                    var item: Item = Item (
                        id: result[i]["id"].stringValue,
                        title: result[i]["title"].stringValue,
                        detail: "detail",
                        imageURL: "http://japan.cnet.com/storage/2013/11/14/98b86da26f62c9e12c07f1d49932d6eb/131114_wemake_180x135.jpg"
                    )
                    self.items?.append(item)
                }
                self.tableView.reloadData()
            }
    }    

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

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

    override func tableView(tableView: UITableView, numberOfRowsInSection section:    Int) -> Int {
        //return 10
        return self.items!.count
    }

    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        return 100;
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell: UITableViewCell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "ItemCell")

        cell.textLabel!.text = self.items?[indexPath.row].title
        cell.detailTextLabel!.text = self.items?[indexPath.row].detail


        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> () in
            var imageURL: NSURL = NSURL(fileURLWithPath: self.items![indexPath.row].imageURL)!
           // var imageData: NSData = NSData(contentsOfURL: imageURL)!
           // var image: UIImage = UIImage(data: imageData)!

            dispatch_async(dispatch_get_main_queue(), { () -> () in
                //cell.imageView!.image = image
            })
        })
        return cell
    }

    override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }

    override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {

    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath:NSIndexPath) {
        performSegueWithIdentifier("show_detail", sender: indexPath)
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "show_detail" {
            var indexPath : NSIndexPath = sender as! NSIndexPath
            var item_id : String = self.items![indexPath.row].id
            var DVController = segue.destinationViewController as! DetailViewController
            DVController.item_id = item_id
        }
    }
}

this is the Item object:

import UIKit

class Item: NSObject {
    var id: String, title: String, detail: String, imageURL: String

    init(id: String, title: String, detail: String, imageURL: String) {
        self.id = id
        self.title = title
        self.detail = detail
        self.imageURL = imageURL
    }
}

I've got no idea how can I filter some rows.

Wonjung Kim · Accepted Answer · 2015-08-23 11:02:33Z

2

You can get the items without ' id == "1" ' like this way.

var items: [Item] = ...
items = items.filter { $0.id != "1"} // This will eliminate items with id == "1".
// it is equivalent to the below line
items = items.filter({ (item:Item)->Bool in item.id != "1"})

Don't forget to call tableView.reloadData() after mutating the items.

edited Aug 23, 2015 at 11:02

answered Aug 23, 2015 at 10:23

Wonjung Kim

1,93315 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Codetard Over a year ago

it keeps saying, cannot invoke 'filter' with an argument list of type '((_) -> _)'

Codetard Over a year ago

I'm adding it below "self.items?.append(item)"

Wonjung Kim Over a year ago

Oh, I didn't noticed that id is String. Please, try items = items.filter { $0.id != "1"}

Wonjung Kim Over a year ago

For clarity of type, this may be better: items = items.filter { (item:Item)->Bool in item.id != "1"}

Wonjung Kim Over a year ago

That's nice. Enjoy your programming.

Collectives™ on Stack Overflow

How can I implement an array filter with Swift?

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related