Swift Custom NSMutableArray Sorting

Question

I have a custom NSMutableArray and i want to sort it; I've looked over the internet but nothing solve my problem. what I have is the following Locations.swift

import UIKit

class Location: NSObject {
    var id:String = String()
    var name:String = String()
    var distance:Float = Float()
}

then I create a Mutable Array from this class in my ViewController.swift

class CustomViewController: UIViewController{
    var locations: NSMutableArray!

    override func viewDidLoad() {
        super.viewDidLoad()
        locations = NSMutableArray()
        locations = SqLite.getInstnace().getLocations()//get values from DB، objects of Location
    }

}

how I can sort locations by the distance value??

there's an easier solution http://stackoverflow.com/questions/24130026/swift-how-to-sort-array-of-custom-objects-by-property-value — Russell, Jan 15 '16 at 17:43

score 3 · Accepted Answer · answered Jan 15 '16 at 17:45

3

I would make location an array of Location objects, and then sorting becomes easy with sortInPlace.

class CustomViewController: UIViewController{
    var locations = [Location]()

    override func viewDidLoad() {
        super.viewDidLoad()
        locations = SqLite.getInstnace().getLocations().flatMap { $0 as? Location }
    }
}

Now you can sort locations like this:

locations.sortInPlace { $0.distance < $1.distance }

answered Jan 15 '16 at 17:45

Aaron Rasmussen

13,082
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Value of type 'NSMutableArray' has no member 'sortInPlace' – Khalil Rumman Jan 15 '16 at 17:46
Did you replace `var locations: NSMutableArray!` with `var locations = [Location]()`? – Aaron Rasmussen Jan 15 '16 at 17:49
thank you :) it worked, I didn't pay attention at first, you saved a lot of time for me – Khalil Rumman Jan 15 '16 at 17:52
2

Also worth mentioning @KhalilRumman you should avvoid using Foundation type objects unless you MUST use them. Stick to the Swift object types. – tskulbru Jan 15 '16 at 18:19

boidkan · Answer 2 · 2016-01-15T20:08:29.487

3

You could always use the built in sort function:

    let locations = SqLite.getInstnace().getLocations().sort({
        return ($0 as! Location).distance < ($1 as! Location).distance
    })

if SqLite.getInstnace().getLocations() return an array as [Location] and not a NSArray then you could just do this since it will already know the elements types:

    let locations = SqLite.getInstnace().getLocations().sort({
        return $0.distance < $1.distance
    })

This should return a sorted array in ascending order if you want descending just use > instead.

Also, there is really no need to use NSMutableArrays in Swift. Just use [Location].

Edit:

NSMutableArray can be used in swift but it considered objective-c like where as using [OBJECT_TYPE] is conventional for swift.

Take a look at the Swift 2 book array segment. None of the examples use NSArray or NSMutable array.

By declaring something with var in swift makes it mutable where as let makes something immutable

edited Jan 15 '16 at 20:08

answered Jan 15 '16 at 17:55

boidkan

4,691
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can you explain to me why I don't need to use NSMutableArrays in swift?? just to keep it in my mind for the future – Khalil Rumman Jan 15 '16 at 18:04
`NSMutableArray` is very object-Cish where as `var locations:[Location]` is more swifty and it is also mutable. If you take a look at the Swift 2 book they don't use anything like NSArray. It's just convention not law. https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/CollectionTypes.html – boidkan Jan 15 '16 at 18:20
Also in the book, `Swift’s Array type is bridged to Foundation’s NSArray class` – boidkan Jan 15 '16 at 18:22

Swift Custom NSMutableArray Sorting

2 Answers2