How to convert JSON to String in ios Swift?

Question

Here is the code for the below Json output:

let params : [[String : AnyObject]]  = [["name" : "action", "value" : "pay" ],["name" : "cartJsonData" , "value" : ["total": 1,"rows":[["quantity": “1” ,"title":"Donation for SMSF India - General Fund","price":"1","itemId":"DN001","cost": “1”,”currency":"INR"]]]], ["name" : "center", "value" : "Chennai"], ["name" : "flatNumber", "value" : "503"], ["name" : "panNumber", "value" : ""], ["name" : "payWith"], ["name" : "reminderFrequency","value" : "Monthly"],  ["name" : "shipToAddr1"], ["name" : "shipToAddr2"], ["name" : "shipToCity"], ["name" : "shipToCountryName" , "value" : "India"], ["name" : "shipToEmail", "value" : “[email protected]"], ["name" : "shipToFirstName" , "value": "4480101010"], ["name" : "shipToLastName"], ["name" : "shipToPhone", "value" : "4480101010"], ["name" : "shipToState"], ["name" : "shipToZip"], ["name" : "userId", "value" : “null”], ["name" : "shipToCountry", "value" : "IN"]]

var jsonObject: NSData? = nil

do {
   jsonObject = try NSJSONSerialization.dataWithJSONObject(params, options: NSJSONWritingOptions())
   print(jsonObject) // This will print the below json. 
} 
catch{}

By printing jsonObject, I got this one.

[{ "value": "pay", "name": "action" }, { "value": { "rows": [{ "price": "1", "quantity": "1", "cost": "1", "currency": "INR", "itemId": "DN001", "title": "Donation for SMSF India - General Fund" }], "total": 1 }, "name": "cartJsonData" }, { "value": "Chennai", "name": "center" }, { "value": "503", "name": "flatNumber" }, { "value": "", "name": "panNumber" }, { "name": "payWith" }, { "value": "Monthly", "name": "reminderFrequency" }, { "name": "shipToAddr1" }, { "name": "shipToAddr2" }, { "name": "shipToCity" }, { "value": "India", "name": "shipToCountryName" }, { "value": "[email protected]", "name": "shipToEmail" }, { "value": "4480101010", "name": "shipToFirstName" }, { "name": "shipToLastName" }, { "value": "4480101010", "name": "shipToPhone" }, { "name": "shipToState" }, { "name": "shipToZip" }, { "value": "null", "name": "userId" }, { "value": "IN", "name": "shipToCountry" }]

And I want the JSON to be in the below format.

[{ “name”: “action”, “value”: “pay” }, { “name”: “cartJsonData”, “value”: “{\”total\”:1,\”rows\”:[{\”itemId\”:\”DN002\”,\”title\”:\”Donation for SMSF India - General Fund\”,\”quantity\”:\”100\”,\”currency\”:\”INR\”,\”price\”:\”1\”,\”cost\”:\”100\”}]}” }, { “name”: “center”, “value”: “Chennai” }, { “name”: “flatNumber”, “value”: “ “ }, { “name”: “panNumber”, “value”: “ASSDDBBDJD” }, { “name”: “payWith” }, { “name”: “reminderFrequency”, “value”: “Monthly” }, { “name”: “shipToAddr1” }, { “name”: “shipToAddr2” }, { “name”: “shipToCity” }, { “name”: “shipToCountryName”, “value”: “India” }, { “name”: “shipToEmail”, “value”: “[email protected]” }, { “name”: “shipToFirstName”, “value”: “Raju” }, { “name”: “shipToLastName” }, { “name”: “shipToPhone”, “value”: “1234567890” }, { “name”: “shipToState” }, { “name”: “shipToZip” }, { “name”: “userId”, “value”: “null” }, { “name”: “shipToCountry”, “value”: “IN” }]

How can it be done? Only the value in cartJsonData needs to be changed. Can someone help me on this to solve it?

What is it that bothers you with the output? It seems like it's a valid json. I am guessing that you don't like the fact that your keys and values order is changed.. In this case you can't fix it, since dictionary does not preserve order of keys, i mean you could still work around that somehow by outputting the json yourself or using some other lib to do that, but that doesn't sound like it's worth it. — igrek
– igrek, Commented Nov 29, 2017 at 15:04
btw, maybe you'd be interested in WritingOptions.sortedKeys option — igrek
– igrek, Commented Nov 29, 2017 at 15:09

Mamad Farrahi · Accepted Answer · 2022-10-26 12:09:53Z

52

Try this.

func jsonToString(json: AnyObject){
        do {
          let data1 =  try NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions.PrettyPrinted) // first of all convert json to the data
            let convertedString = String(data: data1, encoding: .utf8) // the data will be converted to the string
            print(convertedString) // <-- here is ur string  
            
        } catch let myJSONError {
            print(myJSONError)
        }
      
    }

edited Oct 26, 2022 at 12:09

Mamad Farrahi

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answered Apr 2, 2016 at 7:59

ak sacha

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1 Comment

Andy Weinstein Over a year ago

See note above (stackoverflow.com/a/47725685/826946) about using sorting when you want to produce a canonical string that you can use to compare one JSON to another.

BennyTheNerd · Accepted Answer · 2020-12-03 17:16:21Z

25

Swift (as of December 3, 2020)

func jsonToString(json: AnyObject){
    do {
        let data1 =  try JSONSerialization.data(withJSONObject: json, options: JSONSerialization.WritingOptions.prettyPrinted) // first of all convert json to the data
        let convertedString = String(data: data1, encoding: String.Encoding.utf8) // the data will be converted to the string
        print(convertedString ?? "defaultvalue")
    } catch let myJSONError {
        print(myJSONError)
    }
    
}

edited Dec 3, 2020 at 17:16

answered Sep 11, 2017 at 16:10

BennyTheNerd

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1 Comment

vadian Over a year ago

Swift 3 is more than using the changed API syntax. In Swift 3 JSON is Any, the options parameter can be omitted (prettyPrinted is not intended in the question), convertedString can never be nil (even in Swift 2) and in the catch scope you can simply print(error) without a let assignment.

Minh Hoang · Accepted Answer · 2017-12-09 05:41:51Z

16

Swift 4.0

static func stringify(json: Any, prettyPrinted: Bool = false) -> String {
    var options: JSONSerialization.WritingOptions = []
    if prettyPrinted {
      options = JSONSerialization.WritingOptions.prettyPrinted
    }

    do {
      let data = try JSONSerialization.data(withJSONObject: json, options: options)
      if let string = String(data: data, encoding: String.Encoding.utf8) {
        return string
      }
    } catch {
      print(error)
    }

    return ""
}

Usage

stringify(json: ["message": "Hello."])

answered Dec 9, 2017 at 5:41

Minh Hoang

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2 Comments

Andy Weinstein Over a year ago

If you need to compare Json to Json, then add in here the use of sorting - your options should look like this: options: [JSONSerialization.WritingOptions.sortedKeys, JSONSerialization.WritingOptions.prettyPrinted]. Otherwise the order of keys can be different and so logically identical structures might produce non-identical strings.

Andy Weinstein Over a year ago

See also stackoverflow.com/a/46037539/826946 which is where I got the sorting parameter from.

MarkAurelius · Accepted Answer · 2018-04-18 08:41:10Z

Using the new Encodable based API, you can get the string version of a JSON file using String(init:encoding) initialiser. I ran this in a Playground and the last print statement gave me

json {"year":1961,"month":4}

It seems that the format uses the minimum number of characters by detail.

struct Dob: Codable {
    let year: Int
    let month: Int
}

let dob = Dob(year: 1961, month: 4)
print("dob", dob)

if let dobdata = try? JSONEncoder().encode(dob) {
    print("dobdata base64", dobdata.base64EncodedString())
    if let ddob = try? JSONDecoder().decode(Dob.self, from: dobdata) {
        print("resetored dob", ddob)
    }
    if let json = String(data: dobdata, encoding: .utf8) {
      print("json", json)
    }
}

Sazid Iqabal · Accepted Answer · 2020-02-12 10:36:56Z

1

Swift 4.x
xcode 10.x

if you are using Swifty JSON

var stringfyJSOn  = yourJSON.description

For Reference or more information

https://github.com/SwiftyJSON/SwiftyJSON

edited Feb 12, 2020 at 10:36

Sazid Iqabal

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answered Dec 14, 2019 at 21:56

Abdul Karim

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4 Comments

Diego Jiménez Over a year ago

This answer is not working. If the JSON data is a Data object it does not work. You need to make first this operation: let data = try JSONSerialization.data(withJSONObject: json, options: options) if let string = String(data: data, encoding: String.Encoding.utf8) { return string }

Abdul Karim Over a year ago

@wazowski thanks for adding a useful comment, but as per question it was just JSON and nothing mention as JSON data , but yeah if it is data your solu. will work, plz read the question again

Diego Jiménez Over a year ago

you are right the question asks a thing, but the code is telling other, when you receive a data object from the url session you do not receive a Json object like an [String:Any] dictionary, the code of the question is not showing the real JSON data, the question should be 'how can I convert a dictionary to string?'.

Fattie Over a year ago

it's an incredibly bad idea to use any library for json nowadays in iOS. it is absolutely built in to Swift/iOS

tonderaimuchada · Accepted Answer · 2019-10-18 08:06:56Z

0

A simple way to convert a JSON object to a String is: 1. First create a JSON subscript value e.g. jsonObject["fieldName"] 2. Use the '.stringValue' property to retrieve the actually String equivalence (jsonObject["fieldName"].stringValue)

answered Oct 18, 2019 at 8:06

tonderaimuchada

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Comments

Jignesh Kanani · Accepted Answer · 2020-03-03 06:39:21Z

0

Xcode 11, converted String to NSString is working for me.

func jsonToString(json: AnyObject) -> String{
    do {
        let data1 = try JSONSerialization.data(withJSONObject: json, options: JSONSerialization.WritingOptions.prettyPrinted)
        let convertedString = String(data: data1, encoding: String.Encoding.utf8) as NSString? ?? ""
        debugPrint(convertedString)
        return convertedString as String
    } catch let myJSONError {
        debugPrint(myJSONError)
        return ""
    }
}

answered Mar 3, 2020 at 6:39

Jignesh Kanani

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1 Comment

grooot Over a year ago

when I use this I get this error "Argument type 'JSON' expected to be an instance of a class or class-constrained type"

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