I understand what optional are in Swift but I just encountered a ”Double Wrapped Optional’, where if I don’t use two '!' Xcode gives an complier error
Value of optional type 'String?' not unwrapped; did you mean to use '!' or ‘?'?
I have the following code, where app is of type NSRunningApplication.
let name: String = app.localizedName!
Why should I have to use two !? Isn’t one enough to unwrap the variable because it is of type var localizedName: String?.
Context: Xcode want me to use let name: String = app.localizedName!!, otherwise it gives the compiler error above. The app variable is defined as follow:
var apps = NSWorkspace().runningApplications.filter{$0.activationPolicy == NSApplicationActivationPolicy.Regular}
for app in apps{
//code posted above
…
}
So I know that app is not an optional and will always have a value, nor is it an optional application.
P.S. Is there a way to define type when using fast enumeration? Like for Foo(app) in apps where apps = [AnyObject].
The problem is that NSWorkspace().runningApplications returns an array of AnyObject which has to be cast to an array of NSRunningApplication:
let apps = NSWorkspace().runningApplications as! [NSRunningApplication]
let filteredApps = apps.filter {
$0.activationPolicy == NSApplicationActivationPolicy.Regular
}
for app in apps {
let name: String = app.localizedName!
}
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