Get index of array element as Int

Question

I have an array of UIViewController in my protocol

var viewControllers: [MyViewController] { get }

I want to get the index of item with specific ViewController

let idfx = viewModel.viewControllers.index(of: viewController as! MyViewController)

But the type of idfx is Array.index.

How can I get the index of an array element as an Int?

Duncan C · Accepted Answer · 2017-12-06 00:42:17Z

7

The problem isn't that it's of type Array.index, which is a typealias for Int, as Nonuld says. The problem is that it's an optional. You need to unwrap the optional somehow. One way is to use "if let" optional binding:

if let idfx = viewModel.viewControllers.index(of: viewController as! MyViewController) {
  print("view controller found at index \(idfx)") 
} else {
  print("View controller not found in array")
}

edited Dec 6, 2017 at 0:42

answered Dec 5, 2017 at 23:43

Duncan C

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Comments

Arnaud · Accepted Answer · 2017-12-10 20:31:41Z

3

Actually the type Array.Index is a typealias to the type Int, so you can do the same operation as if you had an integer with the result of the method index(of:).

edited Dec 10, 2017 at 20:31

user4639281

answered Dec 5, 2017 at 23:35

Arnaud

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1 Comment

Suma Over a year ago

Beware: this answer ignores the fact the question assumption "But the type of idfx is Array.index" is false. The returned type is optional, see the accepted answer.

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