Question

我有一个使用NSIndexPath作为密钥的字典。它适用于Swift 2，但我找不到一个解决方案，使它适用于Swift 3.我不想使用String作为键，所以请不要建议它。

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

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

编译错误：

Ambiguous reference to member 'subscript'

我尝试了一些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)
}

OR

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

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

在Swift 3中获取Dictionary的值，其中key不是String

1 个答案: