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Initialize a dictionary with non-optional empty arrays in Swift


Initialize a dictionary with non-optional empty arrays in Swift

By : SANDEEP KATUKURI
Date : November 22 2020, 02:59 PM
like below fixes the issue I'm trying to associate an array numerical data with a column label, so I thought I'd model that with a dictionary that maps a string to an array of floats. I'm trying to populate the dictionary by initializing the key values with empty arrays, but I keep getting optional arrays instead. Here is an example, , When you access a dictionary with:
code :
let x = dframe["pine"]


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How to initialize class with optional properties in Swift 3

How to initialize class with optional properties in Swift 3


By : Diana
Date : March 29 2020, 07:55 AM
Does that help I get a web API response, which I loop through and initialize a Customer class for each JSON object in the array. The Customer class has a base class with a couple optional properties. I get errors when there are null values in the JSON, and I am not sure how to handle them properly. I am especially unsure of how to handle a null Date in swift. If anyone could give me some advice, I would really appreciate it! , You need to define your class type for model
code :
 class BaseEntity {
 class BaseEntity: NSObject {
//Model Class
class BaseModel: NSObject {
    var name: String
    var address: String
    var mobilenumber: Int

    init(name: String?, address: String?, mobilenumber: Int?) {
        self.name = name ?? ""
        self.address = address ?? ""
        self.mobilenumber = mobilenumber ?? 0
    }
}

//Pass value inside model class
class ViewController: UIViewController {

    var model = [BaseModel]() //Model Array Initialization here

    override func viewDidLoad() {
        super.viewDidLoad()

        //Pass value inside Model
        model.append(BaseModel(name: "Your name", address: "Your address", mobilenumber: 5545545452))

    }
}

//Get value from Model class
class DetailsController: UIViewController {
    var details: BaseModel?

    override func viewDidLoad() {
        super.viewDidLoad()
       //Retrive value from model
       let name = details?.name ?? ""
       let address = details?.address ?? ""
       let mobile = details?.mobilenumber ?? 0
    }
}
Best way to initialize non-optional var if optional is nil in Swift

Best way to initialize non-optional var if optional is nil in Swift


By : SImon
Date : March 29 2020, 07:55 AM
it fixes the issue You can use the nil-coalescing operator ?? with an "immediately evaluated closure":
code :
let obj = UserDefaults.standard.string(forKey: "my_key") ?? {
    let obj = ProcessInfo.processInfo.globallyUniqueString
    UserDefaults.standard.set(obj, forKey: "my_key")
    return obj
}()

print(obj) // Type is `String`
Swift dictionary with mix types (optional and non-optional)

Swift dictionary with mix types (optional and non-optional)


By : user1839366
Date : March 29 2020, 07:55 AM
it should still fix some issue You can cast frequency to Any since the latter can hold any type. It is like casting instances of specific Swift type to the Objective-C id type. Eventually, you'll have to downcast objects of the type Any to a specific class to be able to call methods and access properties.
I would not recommend structuring data in your code using Any, or if you want to be specific Any? (when the object may or may not hold some value). That would be a sign of bad data-modeling.
code :
struct Record : Codable {
    let name: String
    let frequency: Double?

    init(name: String, frequency: Double?) {
        self.name = name
        self.frequency = frequency
    }

    init(data: Data) throws { 
        self = try JSONDecoder().decode(Record.self, from: data) 
    }

    func toData() -> Data {
        guard let data = try? JSONEncoder().encode(self) else {
            fatalError("Could not encode Record into Data")
        }
        return data
    }
}
let record = Record(name: "Hello", frequency: 13.0)
let data = record.toData()

let decodedRecord = try Record(data: data)
print(decodedRecord.name)
print(decodedRecord.frequency ?? "No frequency")
Initialize and bind swift optional member at the same time?

Initialize and bind swift optional member at the same time?


By : user1901926
Date : March 29 2020, 07:55 AM
it helps some times My class contains optional member properties like this: , You could just move the code inside the didSet of resume.
code :
var resume: Entity? {
    didSet {
        if let resume = self.resume {
            EntityManager.add(resume)
        }
    }
}
Swift remove optional from Dictionary of Dictionary

Swift remove optional from Dictionary of Dictionary


By : Ansuman M
Date : March 29 2020, 07:55 AM
this one helps. All dictionary accesses are returned as optionals because the key used might not exist in the dictionary, and thus nil is returned in that case. You can use optional casting as? along with optional binding if let to make sure the value exists, that it is a dictionary as expected, and unwrap it:
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