Swift 4 JSON 可使用多维和多类型数组解码

Question

{
"values":[
[1,1,7,"Azuan Child","Anak Azuan","12345","ACTIVE","Morning",7,12,"2017-11-09 19:45:00"],
[28,1,0,"Azuan Child2","Amran","123456","ACTIVE","Evening",1,29,"2017-11-09 19:45:00"]
]
}

好的，这是我从服务器收到的json格式

现在我想将它解码到我的结构中，但仍然没有成功。

struct ChildrenTable: Decodable {
    var values: [[String]]?
}

我在 URLSession 上的调用方法如下所示

URLSession.shared.dataTask(with: request) { (data, response, err) in
        guard let data = data else { return }

        let dataAsString = String(data: data, encoding: .utf8)
        print(dataAsString)

        do {
            let children  = try
                JSONDecoder().decode(ChildrenTable.self, from: data)
                print (children)
        } catch let jsonErr {
            print ("Error serializing json: ", jsonErr)
        }
    }.resume()

我得到的错误是

Error serializing json:  
typeMismatch(Swift.String, Swift.DecodingError.Context(codingPath: [Vito_Parent.ChildrenTable.(CodingKeys in _1B826CD7D9609504747BED0EC0B7D3B5).values, Foundation.(_JSONKey in _12768CA107A31EF2DCE034FD75B541C9)(stringValue: "Index 0", intValue: Optional(0)), 
Foundation.(_JSONKey in _12768CA107A31EF2DCE034FD75B541C9)(stringValue: "Index 0", intValue: Optional(0))], 
debugDescription: "Expected to decode String but found a number instead.", underlyingError: nil))

我知道数组中有一个 int，我只为值 var values: [[String]]? 转换字符串（弹出此错误的原因），但我不能在我的结构中使用任何多维数组或元组，因为它遵循 Decodable 的协议。

我也无法将数据转换为字典，因为它会抛出错误 "Expected to decode Dictionary but found array instead"

有什么解决这个问题的想法吗？我尝试在数据上转换字符串类型，但仍然没有成功...

p/s：如果所有 json 格式都是字符串类型，就没有问题，但我没有权限更改它，因为我从 API 调用它.

Answer 1

正如您所说，您的 json 数组是多类型的，但您正试图将其全部解码为 String。 String 与 Decodable 的默认一致性不允许这样做。我想到的唯一解决方案是引入新类型。

struct IntegerOrString: Decodable {
    var value: Any

    init(from decoder: Decoder) throws {
        if let int = try? Int(from: decoder) {
            value = int
            return
        }

        value = try String(from: decoder)
    }
}

struct ChildrenTable: Decodable {
    var values: [[IntegerOrString]]?
}

Run online

Answer 2

观察到 JSON 中的内部数组有一个类型序列，我们知道这个序列是什么。内部数组中的类型按模式序列排列：3 个 Int、5 个字符串、2 个 Int，以及一些可能用作日期的类型。显然，在 JSON 设计者的心目中，这 11 个元素中的每一个都具有固定且已知的含义。

这意味着我们可以通过 dumpster-diving 和手动解码整个 JSON 表达式，手动地一个接一个地拾取 11 个元素。

数组有混合类型，Swift不喜欢这样，所以我们必须将它们表示为 Any（或 AnyObject）的数组；但我们可以获取它们作为自身，而不必将它们包裹在人工中间结构中。

顺便说一句，如果您知道每个元素的含义，那么您可以将内部数组解码为具有 11 个命名属性的结构，而不是 Any 数组，这些属性表示每个元素的含义。那将是一个更清晰的结果，但我没有使用它，因为我不知道这 11 个值的含义。

开始吧：

struct S : Decodable {
    var values : [[Any]]
    enum CodingKeys : String, CodingKey {
        case values
    }
    init(from decoder: Decoder) throws {
        // get the dictionary
        let con = try! decoder.container(keyedBy: CodingKeys.self)
        // get the "values" array of array
        var con2 = try! con.nestedUnkeyedContainer(forKey: CodingKeys.values)
        var bigarr = [[Any]]()
        for _ in 0..<con2.count! {
            // get a nested array
            var con3 = try! con2.nestedUnkeyedContainer()
            // decode all the elements of the nested array
            var arr = [Any]()
            arr.append(try! con3.decode(Int.self))
            arr.append(try! con3.decode(Int.self))
            arr.append(try! con3.decode(Int.self))
            arr.append(try! con3.decode(String.self))
            arr.append(try! con3.decode(String.self))
            arr.append(try! con3.decode(String.self))
            arr.append(try! con3.decode(String.self))
            arr.append(try! con3.decode(String.self))
            arr.append(try! con3.decode(Int.self))
            arr.append(try! con3.decode(Int.self))
            arr.append(try! con3.decode(String.self))
            bigarr.append(arr)
        }
        // all done! finish initialization
        self.values = bigarr
    }
}

let result = try! JSONDecoder().decode(S.self, from: jdata)
print(result.values)
// [[1, 1, 7, "Azuan Child", "Anak Azuan", "12345", "ACTIVE",
// "Morning", 7, 12, "2017-11-09 19:45:00"], 
// [28, 1, 0, "Azuan Child2", "Amran", "123456", "ACTIVE", 
// "Evening", 1, 29, "2017-11-09 19:45:00"]]

Answer 3

我已经尝试在我的项目中使用您的解决方案，它的效果非常棒。下面我做了一些修改，所以它可以用于单个字符串、单个数组和多维数组

struct TripModel: Decodable {
var tx_result: Any
var columns: [Any]
var values: [[Any]]

enum CodingKeys : String, CodingKey {
    case tx_result
    case columns
    case values
}

init(from decoder: Decoder) throws {
    var bigarr = [[Any]]()
    var arrColumn = [Any]()
    // get the dictionary
    let con = try! decoder.container(keyedBy: CodingKeys.self)

    let conResult = try! con.decode(String.self, forKey: CodingKeys.tx_result)

    var conColumns = try! con.nestedUnkeyedContainer(forKey: CodingKeys.columns)
    //print(String(describing: conColumns.count))

    // get the "values" array of array
    var con2 = try! con.nestedUnkeyedContainer(forKey: CodingKeys.values)

    for _ in 0..<con2.count! {
        // get a nested array
        var con3 = try! con2.nestedUnkeyedContainer()
        // decode all the elements of the nested array
        var arr = [Any]()
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(String.self))
        arr.append(try! con3.decode(String.self))
        arr.append(try! con3.decode(String.self))
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(Int.self))
        arr.append(try! con3.decode(Double.self))
        arr.append(try! con3.decode(String.self))
        bigarr.append(arr)
    }

        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))
        arrColumn.append(try! conColumns.decode(String.self))

    // all done! finish initialization
    self.tx_result = conResult
    self.columns = arrColumn
    self.values = bigarr
}

}

Answer 4

这个答案建立在 @Orkhan Alikhanov

的答案之上

由于值为 Int 或 String，我们可以用枚举代替 Any.

来更好地表示它们

The following code can be pasted into Playground

JSON

所以让我们从 JSON

开始

let data = """
{
    "values": [
        [1, 1, 7, "Azuan Child", "Anak Azuan", "12345", "ACTIVE", "Morning", 7, 12, "2017-11-09 19:45:00"],
        [28, 1, 0, "Azuan Child2", "Amran", "123456", "ACTIVE", "Evening", 1, 29, "2017-11-09 19:45:00"]
    ]
}
""".data(using: .utf8)!

数据模型

现在我们可以定义我们的模型（它将是Decodable）

enum IntOrString: Decodable {

    case int(Int)
    case string(String)

    init(from decoder: Decoder) throws {

        if let string = try? decoder.singleValueContainer().decode(String.self) {
            self = .string(string)
            return
        }

        if let int = try? decoder.singleValueContainer().decode(Int.self) {
            self = .int(int)
            return
        }

        throw IntOrStringError.intOrStringNotFound
    }

    enum IntOrStringError: Error {
        case intOrStringNotFound
    }
}

As you can see we are explicitly saying that each value will be an Int or a String.

回应

当然我们需要 Response 类型。

struct Response: Decodable {
    var values: [[IntOrString]]
}

解码

现在我们可以安全地解码 JSON

if let response = try? JSONDecoder().decode(Response.self, from: data) {
    let values = response.values

    for value in values {
        for intOrString in value {
            switch intOrString {
            case .int(let int): print("It's an int: \(int)")
            case .string(let string): print("It's a string: \(string)")
            }
        }
    }
}

输出

It's an int: 1
It's an int: 1
It's an int: 7
It's a string: Azuan Child
It's a string: Anak Azuan
It's a string: 12345
It's a string: ACTIVE
It's a string: Morning
It's an int: 7
It's an int: 12
It's a string: 2017-11-09 19:45:00
It's an int: 28
It's an int: 1
It's an int: 0
It's a string: Azuan Child2
It's a string: Amran
It's a string: 123456
It's a string: ACTIVE
It's a string: Evening
It's an int: 1
It's an int: 29
It's a string: 2017-11-09 19:45:00

Answer 5

解决方案

public struct UncertainValue<T: Decodable, U: Decodable>: Decodable {
    public var tValue: T?
    public var uValue: U?

    public var value: Any? {
        return tValue ?? uValue
    }

    public init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        tValue = try? container.decode(T.self)
        uValue = try? container.decode(U.self)
        if tValue == nil && uValue == nil {
            //Type mismatch
            throw DecodingError.typeMismatch(type(of: self), DecodingError.Context(codingPath: [], debugDescription: "The value is not of type \(T.self) and not even \(U.self)"))
        }

    }
}

例子

{
"results": [{
        "name": "Gala",
        "age": 1,
        "type": "Pug"
    }, {
        "name": "Keira",
        "age": "7",
        "type": "Collie Rough"
    }]
}

用法

struct Dog: Decodable, CustomStringConvertible {
    var name: String
    var age: UncertainValue<Int, String>
    var type: String

    var description: String {
        return "\(name) is a lovely \(type) of \(age.value!) years old"
    }
}

Swift 4 JSON 可使用多维和多类型数组解码

Swift 4 JSON Decodable with multidimensional and multitype array

arrays

json

multidimensional-array

swift4

decodable

JSON

数据模型

回应

解码

输出