获取 Swift 中 Dictionary 的值 3 哪个键不是字符串

Question

我有一个使用 NSIndexPath 作为键的字典。它适用于 Swift 2，但我找不到使它适用于 Swift 3 的解决方案。我不想使用 String 作为键，所以请不要建议。

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

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

编译器错误：

Ambiguous reference to member 'subscript'

一些我试过但不起作用的解决方案：

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
}

Answer 1

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

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

或

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

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