Get value of Dictionary in Swift 3 which key isn't a String

Question

I have a dictionary used NSIndexPath as key. It works fine with Swift 2 but I can't find a solution to make it work with Swift 3. I don't want to use String as a key so please don't suggest it.

// init
fileprivate var cachedCellSizes: [NSIndexPath: CGSize] = [:] 

// get value 
if let size = cachedCellSizes[indexPath] {
    return size
}

Compiler error:

Ambiguous reference to member 'subscript'

Some solution I had tried but doesn't work:

if let size:CGSize = cachedCellSizes[indexPath] as? CGSize {
    return size
}
if let size:CGSize = cachedCellSizes[indexPath] as! CGSize {
    return size
}
if let size:CGSize = cachedCellSizes["indexPath"] as CGSize {
    return size
}

Please check that your indexPath is actually a `NSIndexPath`. Coz Swift 3 uses `IndexPath` (not `NSIndexPath`) in table delegate methods. If so you can use `if let size = cachedCellSizes[indexPath as! NSIndexPath]` or change dictionary key as `IndexPath` — RJE, Nov 24 '16 at 02:31

score 1 · Accepted Answer · answered Nov 24 '16 at 02:36

1

fileprivate var cachedCellSizes: [NSIndexPath: CGSize] = [:]

if let size = cachedCellSizes[indexPath as NSIndexPath] {
    print(indexPath)
}

OR

fileprivate var cachedCellSizes: [IndexPath: CGSize] = [:]

if let size = cachedCellSizes[indexPath] {
    print(indexPath)
}

answered Nov 24 '16 at 02:36

Callam

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The second method is preferable. – Alexander Nov 24 '16 at 06:34
@AlexanderMomchliov is right, the second is preferable since you're using Swift 3. – Callam Nov 24 '16 at 15:07

Get value of Dictionary in Swift 3 which key isn't a String

1 Answers1