Key-Value Coding (KVC) with Array/Dictionary in Swift

问题

Is it possible to key-value code (KVC) with native Swift data structures such as Array and Dictionary? Key-Value coding is still available for NSFoundation structures within Swift, just like in Objective C.

For example, this is valid:

var nsarray: NSArray = NSArray()
// Fill the array with objects
var array: NSArray = nsarray.valueForKeyPath("key.path")

But this is invalid:

var swiftarray: Array = []
// Fill the array with objects
var array = swiftarray.valueForKeyPath("key.path") // Invalid, produces a compile-time error

回答1:

It seems that KVC on native Swift objects is just not supported. Here's the most elegant workaround I've found:

var swiftarray: Array = []
// Fill the array with objects
var array: NSArray = (swiftarray as NSArray).valueForKeyPath("key.path") as NSArray

回答2:

I've found this:

var array = swiftarray.map({$0["key.path"]! as ObjectType})

回答3:

you can do the following:

let items : Array<String> = (myArray as AnyObject).valueForKeyPath("name") as! Array<String>

回答4:

How about this:

let names = array.map { $0.name }

Instead of using key paths you can directly refer to property or method.

来源：https://stackoverflow.com/questions/26367261/key-value-coding-kvc-with-array-dictionary-in-swift