Convert Json to Array in Swift 5

Question

All the examples I find are using dictionary types, for example: user: x, book: y

but how can I convert this type of Json which doesn't contain a key?

["1","137","56","56"]

This is of type String?

I tried:

struct Candidate: Decodable {
    var S: String?
}

let chainsAllowed = ["1","137","56","56"]

let jsonObjectData = chainsAllowed.data(using: .utf8)!
let candidate = try? JSONDecoder().decode(
    Candidate.self,
    from: jsonObjectData
)

but I get nil. How can I convert it into an array?

Thanks

'["1","137","56","56"]' is not even in the JSON format, duh... — El Tomato
– El Tomato, Commented Aug 11, 2021 at 2:00
JSON format be like ["userA": "1", "userB": "137", "userC": "56", "userD": "56"], bro — sonle
– sonle, Commented Aug 11, 2021 at 2:04
try? is literally saying "If there are any errors, please disregard them and just give me nil". If you caught the error instead and took a look at it, you would have gotten a useful error message. — Alexander
– Alexander, Commented Aug 11, 2021 at 2:18
For anyone saying it's not even JSON, it actually is valid JSON. A JSON text can be any of false / null / true / object / array / number / string. See datatracker.ietf.org/doc/html/rfc8259#section-2 — Miigon
– Miigon, Commented Aug 11, 2021 at 2:23
@ElTomato lol it is. It's actually downloaded from AWS DyanamoDB with type: AWSJSON — Albert
– Albert, Commented Aug 11, 2021 at 2:26

Miigon · Accepted Answer · 2021-08-11 03:14:54Z

4

Do this:

import Foundation

let chainsAllowed = #"["1","137","56","56"]"#

let jsonObjectData = chainsAllowed.data(using: .utf8)
let candidate = try? JSONDecoder().decode(
    [String].self,
    from: jsonObjectData!
)

print(candidate!)

Output:

["1", "137", "56", "56"]

For your information: An array is actually perfectly valid JSON. In fact, a JSON text can be any of false / null / true / object / array / number / string. See https://datatracker.ietf.org/doc/html/rfc8259#section-2

edited Aug 11, 2021 at 3:14

answered Aug 11, 2021 at 2:14

Miigon

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