Convert Array of Dictionary to custom object swift

Question

I have:

    let countries : [[String : Any]] = [
            [
                "name" : "Afghanistan",
                "dial_code": "+93",
                "code": "AF"
            ],
            [
                "name": "Aland Islands",
                "dial_code": "+358",
                "code": "AX"
            ],
            [
                "name": "Albania",
                "dial_code": "+355",
                "code": "AL"
            ],
            [
                "name": "Algeria",
                "dial_code": "+213",
                "code": "DZ"
            ]
]

I want to add all this array of dictionary to my custom object like

let country:[Country] = countries

My custom object looks like this:

class Country: NSObject {
        let name: String
        let dial_code : String
        let code: String

        init(name: String, dial_code: String, code: String) {
            self.name = name
            self.dial_code = dial_code
            self.code = code
        }
    }

I understand that I need a loop thru the array but idk what is the next step. Would be great to have an example.

Answer 1

You should make your Country conform to Codable protocol, convert your dictionary to JSON data using JSONSerialization and then just decode the Data using JSONDecoder , note that you can set its keyDecodingStrategy property to convertFromSnakeCase auto avoid the need to declare custom coding keys like dial_Code :

struct Country: Codable {
    let name: String
    let dialCode : String
    let code: String
}

---

do {
    let json = try JSONSerialization.data(withJSONObject: countries)
    let decoder = JSONDecoder()
    decoder.keyDecodingStrategy = .convertFromSnakeCase
    let decodedCountries = try decoder.decode([Country].self, from: json)
    decodedCountries.forEach{print($0)}
} catch {
    print(error)
}

---

Country(name: "Afghanistan", dialCode: "+93", code: "AF")

Country(name: "Aland Islands", dialCode: "+358", code: "AX")

Country(name: "Albania", dialCode: "+355", code: "AL")

Country(name: "Algeria", dialCode: "+213", code: "DZ")

Answer 2

Not related but remove NSObject until you are required

That is very simple thing you just need to think a bit

Create Object like this

var arr = [Country]()

Now Loop your array of dictionary

  for dict in countries {
      // Condition required to check for type safety :)
        guard let name = dict["name"] as? String, 
              let dialCode = dict["dial_code"] as? String, 
              let code = dict["code"] as? String else {
              print("Something is not well")
             continue
         }
        let object = Country(name: name, dial_code:dialCode, code:code)
         arr.append(object)
    }
  

That's it You have converted array of dict to Custom Object

Hope it is helpful to you

Answer 3

You can use flatMap method of a list to produce the result:

countries.flatMap { (v: [String: Any]) -> Country? in
    if let name = v["name"] as? String, 
       let dial = v["dial_code"] as? String, 
       let code = v["code"] as? String {
        return Country(name: name, dial_code: dial, code: code)
    } else {
        return nil
    }
}

A full example would be:

//: Playground - noun: a place where people can play

import UIKit

let countries : [[String : Any]] = [
    [
        "name" : "Afghanistan",
        "dial_code": "+93",
        "code": "AF"
    ],
    [
        "name": "Aland Islands",
        "dial_code": "+358",
        "code": "AX"
    ],
    [
        "name": "Albania",
        "dial_code": "+355",
        "code": "AL"
    ],
    [
        "name": "Algeria",
        "dial_code": "+213",
        "code": "DZ"
    ]
]

class Country: NSObject {
    let name: String
    let dial_code : String
    let code: String

    init(name: String, dial_code: String, code: String) {
        self.name = name
        self.dial_code = dial_code
        self.code = code
    }
}

let cnt = countries.flatMap { (v: [String: Any]) -> Country? in
    if let name = v["name"] as? String, let dial = v["dial_code"] as? String, let code = v["code"] as? String {
        return Country(name: name, dial_code: dial, code: code)
    } else {
        return nil
    }
}

print (cnt)

Answer 4

There are a lot of answers already, but I find that there are short comings with most of them. This is what I would suggest:

extension Country {
    init?(fromDict dict: [String: Any]) {
        guard let name = dict["name"] as? String, 
              let dialCode = dict["dial_code"] as? String, 
              let code = dict["code"] as? String else {
            return nil
        }
        self.init(name: name, dialCode: dialCode, code: code)
    }
}

let countries = countryDictionaries.map { dict -> Country in
    if let country = Country(fromDict: dict) { return Country }
    else {
        preconditionFailure("Tried to convert an invalid dict into a country")
        // TODO: handle error appropriately
    }
}

If you just want to ignore invalid country dictionaries, that's even easier:

let countries = countryDictionaries.flatMap(Country.init(fromDict:))

Answer 5

Very simple and clear solution:

• Create custom initializer with param json [String : Any] in your class Country .
• Init all variables of class using loop in custom initializer.

Try this code:

class Country: NSObject {
    var name: String = ""
    var dial_code: String = ""
    var code: String = ""

    // Sol: 1
    init(json: [String : Any]) {
        if let name = json["name"] as? String, let dial_code = json["dial_code"] as? String, let code = json["name"] as? String {
            self.name = name
            self.dial_code = dial_code
            self.code = code
        }
    }

    // or Sol: 2
    init(name: String, dial_code: String, code: String) {
        self.name = name
        self.dial_code = dial_code
        self.code = code
    }
}

• Create an instance of class Countries using element of array countries and collect the same in separate array arrayOfCountries

Try this code:

let countries : [[String : Any]] = [
    [
        "name" : "Afghanistan",
        "dial_code": "+93",
        "code": "AF"
    ],
    [
        "name": "Aland Islands",
        "dial_code": "+358",
        "code": "AX"
    ],
    [
        "name": "Albania",
        "dial_code": "+355",
        "code": "AL"
    ],
    [
        "name": "Algeria",
        "dial_code": "+213",
        "code": "DZ"
    ]
]

var arrayOfCountries = [Country]()

// Sol: 1
for json in countries {
    let country = Country(json: json)
    print("country name - \(country.name)")
    arrayOfCountries.append(country)
}

// Sol: 2
for json in countries {

    if let name = json["name"] as? String, let dial_code = json["dial_code"] as? String, let code = json["name"] as? String {
        let country = Country(name: name, dial_code: dial_code, code: code)
        print("country name - \(country.name)")
        arrayOfCountries.append(country)
    }

}

Answer 6

Create a custom country class with param json [String : Any]

class Country: NSObject {
    var name: String?
    var dialCode: String?
    var code: String?

    init(json: [String : Any]) {
       self.name = json["name"] as? String
       self.dialCode = json["dial_code"] as? String
       self.code = json["code"] as? String
    }
}

Later you can map the dictionary into the array of country using

let _ = countries.flatMap { Country.init }

Answer 7

Here is a useful extension that infers the type from the pre-defined return type:

extension Dictionary {
    func castToObject<T: Decodable>() -> T? {
        let json = try? JSONSerialization.data(withJSONObject: self)
        return json == nil ? nil : try? JSONDecoder().decode(T.self, from: json!)
    }
}

Usage would be:

struct Person: Decodable {
  let name: String
}

let person: Person? = ["name": "John"].castToObject()
print(person?.name) // Optional("John")

Answer 8

First you need to initialize an empty array type of Country Class

var countryArray = [Country]()
//then you have to loop thru the countries dictionary 
//and after casting them adding it to this empty array with class initializer  

countries.forEach { (dict) in

    countryArray.append(Country(name: dict["name"] as! String, dial_code: dict["dial_code"] as! String, code: dict["code"] as! String))

}
//this is how you reach to properties
countryArray.forEach { (country) in
    print(country.name)
}

Answer 9

You can map the dictionary into the array. As a dictionary always returns an optional value for key (the value is not guaranteed to exist) you need a guard to make sure you proceed only if that is the case.

In this sample solution I throw if any of the values are not there - but this is really up to you to decide.

struct AnError: Error {}

do {
    let countryObjects: [Country] = try countries.map {
        guard let name = $0["name"] as? String,
              let dial_code = $0["dial_code"] as? String,
              let code = $0["code"] as? String else {throw AnError()}

        return Country(name: name, dial_code: dial_code, code: code)
    }
}
catch {
    //something went worng - handle the error
}

Answer 10

you can use Array.foreach like this

countries.forEach{country.append(Country($0))}

and u may change init parameters of Country to [String: Any] , or cast $0 to [String: Any] and read ur values from it and send them to init