Convert NSDictionary to Swift Dictionary

Question

Now I know that when swift compiles it just makes a NSDictionary, but the NSDictionary and Swift dictionaries have different syntax. Is there a way (through a loop or something) to convert a NSDictionary to a swift dictionary of the same type for <key, value>?

OR

Is there a way to convert this to a Swift dictionary instead of NSDictionary?

let jsonDict = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &error) as NSDictionary

Gelding

under the hood the Swift Dictionary is literally an Obj-C NSMutableDictionary, you can bridge them toll-free. – Spanjian

Answer 1

use:

let jsonDic = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: &error) as Dictionary<String, AnyObject>;

Ryley

For some reason, that didn't work for me. What worked for me was let b = d as [NSObject:AnyObject] – Ilocano

For SWIFT 3 you can use JSONSerialization. – Lockard

Answer 2

I found answer from http://www.swift-studies.com/blog/2014/6/6/loading-a-swift-dictionary-from-a-plist-file

var swiftDict : Dictionary<String,AnyObject!> = Dictionary<String,AnyObject!>()
for key : AnyObject in ocDictionary.allKeys {
    let stringKey = key as String 
    if let keyValue = ocDictionary.valueForKey(stringKey){
        swiftDict[stringKey] = keyValue
    }
}

Unchartered

Maybe in some very specific cases that may pay off, but I don't think that the overhead in memory, cpu and battery use of making a shallow copy of the NSDictionary has any real advantage. Since you can use an NSDictionary as a regular Dictionary the difference is almost non existent. – Headliner

Answer 3

NSDictionary and Dictionary are pretty much interchangeable. So there's no need to, but yes you can:

let jsonDict = (NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &error) as NSDictionary) as Dictionary

Shorttempered

Are they what? Interchangeable with their counterparts? Yes. – Shorttempered

I keep having to type out as NSString everywhere though and ti doesn't like as String. Maybe this is because I'm defining jsonDict : [[String:AnyObject]]? – Shuttlecock

I believe it is, when going from AnyObject to anything, you have to cast it. – Shorttempered

Beware bridging if NSDictionary to Dictionary is not toll free. – Irrepealable