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

Question

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

do you mean swiftarray at the last line of code?

return true
– return true

2014-10-14 18:05:27 +00:00
Commented Oct 14, 2014 at 18:05 — return true
– return true, Commented Oct 14, 2014 at 18:05
Check out this post by Matt Long: cimgf.com/2014/11/05/…

Drew C
– Drew C

2015-06-30 16:38:37 +00:00
Commented Jun 30, 2015 at 16:38 — Drew C
– Drew C, Commented Jun 30, 2015 at 16:38

kev · Accepted Answer · 2014-10-14 18:14:49Z

11

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

answered Oct 14, 2014 at 18:14

kev

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Comments

Phoenix · Accepted Answer · 2015-06-07 11:52:23Z

8

I've found this:

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

answered Jun 7, 2015 at 11:52

Phoenix

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Comments

Grégoire Aubin · Accepted Answer · 2016-05-17 12:29:01Z

2

you can do the following:

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

answered May 17, 2016 at 12:29

Grégoire Aubin

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Comments

vahotm · Accepted Answer · 2019-02-04 15:06:27Z

1

How about this:

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

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

answered Feb 4, 2019 at 15:06

vahotm

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