How to convert a string into JSON using SwiftyJSON

Question

The string to convert:

[{"description": "Hi","id":2,"img":"hi.png"},{"description": "pet","id":10,"img":"pet.png"},{"description": "Hello! :D","id":12,"img":"hello.png"}]

The code to convert the string:

var json = JSON(stringLiteral: stringJSON)

The string is converted to JSON and when I try to count how many blocks are inside this JSON (expected answer = 3), I get 0.

print(json.count)

Console Output: 0

What am I missing? Help is very appreciated.

When I print the "json" it shows me all the data, but when I print "json.count" it shows me 0 and not 3 :C — Gabo Cuadros Cardenas, Apr 19 '16 at 22:46

score 60 · Answer 1 · edited Mar 25 '19 at 08:56

60

Actually, there was a built-in function in SwifyJSON called parse

/**
 Create a JSON from JSON string
- parameter string: Normal json string like '{"a":"b"}'

- returns: The created JSON
*/
public static func parse(string:String) -> JSON {
    return string.dataUsingEncoding(NSUTF8StringEncoding)
        .flatMap({JSON(data: $0)}) ?? JSON(NSNull())
}

Note that

var json = JSON.parse(stringJSON)

its now changed to

var json = JSON.init(parseJSON:stringJSON)

edited Mar 25 '19 at 08:56

SBotirov

13,872
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answered Aug 25 '16 at 00:26

HamGuy

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18

4

Constructor parameter has been renamed parseJSON → JSON.init(parseJSON: stringJSON) – Maximelc Jun 22 '18 at 18:06
This should be the accepted answer because it avoids to create a temporary Data object. – Lensflare Nov 05 '18 at 09:48
1

Argument label `parseString` gives me an error. This worked for me `JSON.init(parseJSON:stringJSON)` – Leonard Jan 30 '19 at 18:35
please move this var json = JSON.init(parseJSON:stringJSON) on top of your answer – nickeyzzz Jun 08 '20 at 08:09
OMG you saved me – Abhishek Thapliyal Jun 05 '21 at 05:50

score 15 · Accepted Answer · edited Dec 27 '20 at 14:57

I fix it on this way.

I will use the variable "string" as the variable what contains the JSON.

1.

encode the sting with NSData like this

var encodedString : NSData = (string as NSString).dataUsingEncoding(NSUTF8StringEncoding)!

un-encode the string encoded (this may be sound a little bit weird hehehe):

var finalJSON = JSON(data: encodedString)

Then you can do whatever you like with this JSON.

Like get the number of sections in it (this was the real question) with

finalJSON.count or print(finalJSON[0]) or whatever you like to do.

score 5 · Answer 3 · answered Jun 25 '21 at 15:46

5

There is a built-in parser in SwiftyJSON:

let json = JSON.init(parseJSON: responseString)

Don't forget to import SwiftyJSON!

answered Jun 25 '21 at 15:46

BabakHSL

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score 2 · Answer 4 · answered Nov 22 '16 at 17:58

2

I'm using as follows:

let yourString = NSMutableString()

let dataToConvert = yourString.data(using: String.Encoding.utf8.rawValue)

let json = JSON(data: dataToConvert!)

print("\nYour string: " + String(describing: json))

answered Nov 22 '16 at 17:58

Machado

14,105
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score 1 · Answer 5 · answered Sep 03 '18 at 06:19

1

Swift4

let json = string.data(using: String.Encoding.utf8).flatMap({try? JSON(data: $0)}) ?? JSON(NSNull())

answered Sep 03 '18 at 06:19

Maxim Firsoff

2,038
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It doesn't compile because $0 is UInt8 and not a valid parameter type for JSON(data:). Despite not compiling, I don't see how this would result in json because it makes an array (flatMap). – Lensflare Nov 05 '18 at 09:46
The part `$0` is used within ForEach loops, so it could technically work. – Unterbelichtet Apr 13 '21 at 14:21

How to convert a string into JSON using SwiftyJSON

5 Answers5