I am trying to convert time series data received from the website alpha vantage to Swift object however the error message shown below prevents it from happening. Also my network function works. How do I resolve this ?

https://www.alphavantage.co/query?function=TIME_SERIES_MONTHLY_ADJUSTED&symbol=IBM&apikey=demo

keyNotFound(CodingKeys(stringValue: "meta", intValue: nil), Swift.DecodingError.Context(codingPath: [], debugDescription: "No value associated with key CodingKeys(stringValue: \"meta\", intValue: nil) (\"meta\").", underlyingError: nil))

struct TimeSeriesMonthlyAdjusted :Decodable{
    let meta: Meta
    let timeSeries: [String:OHLC]
}

struct Meta :Decodable{
    let symbol:String
    enum CodingKey:String{
        case symbol = "2. Symbol"
    }
}

struct OHLC : Decodable{
    let open :String
    let close : String
    let adjustedClose: String
    
    enum CodingKey:String{
        case open = "1. open"
        case close = "4. close"
        case adjustedClose = "5. adjusted close"

    }
    
}

CodePudding user response：

So two things (which worked for me). Adding CodingKey support TimeSeriesMonthlyAdjusted

struct TimeSeriesMonthlyAdjusted :Decodable{
    enum CodingKeys:String, CodingKey {
        case meta = "Meta Data"
        case timeSeries = "Monthly Adjusted Time Series"
    }
    let meta: Meta
    let timeSeries: [String:OHLC]
}

and changing enum CodingKey: String {...} to enum CodingKeys: String, CodingKey {...} for all your structs

Playground test

Make sure you add Test.json to the Resources folder in the Playground

struct TimeSeriesMonthlyAdjusted :Decodable{
    enum CodingKeys:String, CodingKey {
        case meta = "Meta Data"
        case timeSeries = "Monthly Adjusted Time Series"
    }
    let meta: Meta
    let timeSeries: [String:OHLC]
}

struct Meta :Decodable{
    let symbol:String
    enum CodingKeys:String, CodingKey{
        case symbol = "2. Symbol"
    }
}

struct OHLC : Decodable{
    let open :String
    let close : String
    let adjustedClose: String
    
    enum CodingKeys:String, CodingKey {
        case open = "1. open"
        case close = "4. close"
        case adjustedClose = "5. adjusted close"

    }
}


do {
    let data = try Data(contentsOf: Bundle.main.url(forResource: "Test", withExtension: "json")!)
    try JSONDecoder().decode(TimeSeriesMonthlyAdjusted.self, from: data)
} catch let error {
    error
}

You might also want to make use of https://app.quicktype.io for quickly converting JSON to Swift