Convert Swift Dictionary to Nsdictionary

How do I convert swift Dictionary to NSDictionary

You have to cast it like this:

let dict = parcelDict as NSDictionary

Otherwise the Swift Dictionary and NSDictionary are treated almost the same way when using it in methods for ex:

func test(dict: NSDictionary) {}

let dict = ["Test":1]
test(dict)

Will work completely fine.

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After your update

If you change your Dictionary value type to non optional String then your error will go away.

[String:String?] change to -> [String:String]

Convert Swift Dictionary to NSDictionary

Try parms.bridgeToObjectiveC(). That may give you an NSDictionary rather than an NSMutableDictionary, though.

Swift Dictionary [String:String] to NSMutableDictionary?

There’s no built-in cast for this. But instead you can use NSMutableDictionary’s initializer that takes a dictionary:

var foundationDictionary = NSMutableDictionary(dictionary: dictionary)

How do I convert NSDictionary to Dictionary?

• NSDictionary in Objective-C has always non-optional values.
• AnyObject has become Any in Swift 3.
• Considering the first two "rules" NSDictionary can be bridge cast to Dictionary

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let post_paramsValue = post_params as Dictionary<String,Any>

If the source NSDictionary is an optional you might use as Dictionary<String,Any>? or as? Dictionary<String,Any> or as! Dictionary<String,Any> or as Dictionary<String,Any>! depending on the actual type of the NSDictionary

Convert from NSDictionary to [String:Any?]

Hope this helps:

let dict = NSDictionary()
var anyDict = [String: Any?]()

for (value, key) in dict {
    anyDict[key as! String] = value
}

convert JSON dictionary to NSDictionary

You can get an int or a string from SwiftyJSON objects by using the following functions: .stringValue, .intValue, .boolValue, .doubleValue etc.

Convert Swift Dictionary With Enum Value To NSDictionary

NSJSONSerialize and friends can only deal with small subset of NSObject children (NSNumber, NSString, NSArray, NSDictionary, and NSNull) that correspond to the JSON native data types. In addition, a Dictionary can only be converted to an NSDictionary if both the key and value are NSObject or inherently convertible to NSObject (String and numeric types).

In order to serialize your Dictionary you'll need to convert the Enum to one of those NSJSONSerialize data-types, similar to your example:

enum MyEnum : String {
    case one = "one"
    case two = "two"
}

let dict = ["one":MyEnum.one, "two":MyEnum.two]

var newDict = Dictionary<String, String>()
for (key, val) in dict {
    newDict[key] = val.rawValue
}

let data = NSJSONSerialization.dataWithJSONObject(newDict, options: .allZeros, error: nil)

As an alternative, since this kind of manipulation is fairly common, you might want to consider adding this category to Dictionary, which gives it a convenient map function:

extension Dictionary {
    init(_ pairs: [Element]) {
        self.init()
        for (k, v) in pairs {
            self[k] = v
        }
    }

    func map<K: Hashable, V>(transform: Element -> (K, V)) -> [K: V] {
        return Dictionary<K, V>(Swift.map(self, transform))
    }
}

Once that's done, the conversion is simply:

let mapped = dict.map { (key, value) in (key, value.rawValue) }

What is the difference between these two options for converting Swift Dictionary to NSMutableDictionary?

This works in most cases

No, this works not at all.

Unlike immutable NSDictionary Swift Dictionary and NSMutableDictionary are not related.

You can bridge cast (as without ?) [String:String] to NSDictionary but you cannot bridge cast nor conditionally downcast (as?) it to NSMutableDictionary.

The second syntax works because a new instance of NSMutableDictionary is created. The Swift dictionary parameter is implicitly bridged to NSDictionary

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The same behavior is also true for Swift Array and Foundation NSMutableArray

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