Is there a tangible benefit to using “self” outside of closures?

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Category:Languages

I have noticed a few people in the industry will use the self keyword even when not explicitly required (i.e. outside of closures).

Example:

import UIKit import MapView import CoreLocation  class viewController: UIViewController, MKMapViewDelegate, CLLocationDelegate {      let mapView = MKMapView()     let locationManager = CLLocationManager()      override func viewDidLoad() {         super.viewDidLoad()          self.mapView.delegate = self         self.mapView.showsUserLocation = true          self.locationManager.delegate = self         self.locationManager.desiredAccuracy = kCLLocationAccuracyBest     } } 

Is there a tangible benefit to this, runtime-wise? Or is this purely a stylistic choice?

 


There is.

In the examples you provided, it makes no difference, it's purely a style choice. Some people might like it since it explicitly tells you you're modifying self, personally, I think it looks cleaner without.

Where it matters is when you have a local variable with the same name. Let's say you have a class that has a var count: Int property. Then, in one of your methods, you declare a new variable with the same name.

The local variable will be used whenever you type count, so if you want to modify or read the object's variable, you'll need to use self.

Some examples where it makes a difference:

guard let count = calculateCount() as? Int else { return } self.count = count  init(count: Int) {   self.count = count }  func updateCount(_ count: Int) {   self.count = count } 

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