如何快速从json数据中获取特定值

Question

I am trying to pull a certain value from a json. In this case I am trying to get the value of 'isethanawake' which should be 1 in this case from:

Optional([{"isethanawake":1,"name":"Ethan"},{"ismadisonawake":0,"name":"Madison"},{"ismomawake":0,"name":"Mom"},{"isdadawake":0,"name":"Dad"}]

Here is the code I have and it is not setting the variable to 1

var isethanawake = 0
var ismadisonawake = 0
var ismomawake = 0
var isdadawake = 0

request2.httpBody = postString2.data(using: String.Encoding.utf8)

let task2 = URLSession.shared.dataTask(with: request2 as URLRequest){
    data, response, error in

    if error != nil{
        print("error = \(error)")
        return
    }

    print("response = \(response)")

    let responseString = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
    print("responseString = \(responseString)")

    do{
        let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary

        if let parseJSON1 = json {
            isethanawake = parseJSON1["isethanawake"] as! Int

        }
        if let parseJSON2 = json{
            ismadisonawake = parseJSON2["ismadisonawake"] as! Int
        }


        if let parseJSON3 = json{
            ismomawake = parseJSON3["ismomawake"] as! Int
        }

        if let parseJSON4 = json{
            isdadawake = parseJSON4["isdadawake"] as! Int
        }

        print("hello" + String(isethanawake))
    }catch{
        print(error)
    }

It is getting the data from this php script:

$jsonarray = array();

if(mysqli_num_rows($ethanresult)){
    $returnValue1 = array("isethanawake"=> 1, "name"=> "Ethan");
    array_push($jsonarray, $returnValue1);
}else{
    $returnValue1 = array("isethanawake"=> 0, "name"=> "Ethan");
    array_push($jsonarray, $returnValue1);
}
if(mysqli_num_rows($madisonresult)){
    $returnValue2 = array("ismadisonawake"=> 1, "name"=> "Madison");
    array_push($jsonarray, $returnValue2);
}else{
    $returnValue2 = array("ismadisonawake"=> 0, "name"=> "Madison");
    array_push($jsonarray, $returnValue2);
}
if(mysqli_num_rows($momresult)){
    $returnValue3 = array("ismomawake"=> 1, "name"=> "Mom");
    array_push($jsonarray, $returnValue3);
}else{
    $returnValue3 = array("ismomawake"=> 0, "name"=> "Mom");
    array_push($jsonarray, $returnValue3);
}
if(mysqli_num_rows($dadresult)){
    $returnValue4 = array("isdadawake"=> 1, "name"=> "Dad");
    array_push($jsonarray, $returnValue4);
}else{
    $returnValue4 = array("isdadawake"=> 0, "name"=> "Dad");
    array_push($jsonarray, $returnValue4);

}
echo json_encode($jsonarray);

}

Thanks

Answer 1

As you said your your JSON structure is:

Optional([{"isethanawake":1,"name":"Ethan"},{"ismadisonawake":0,"name":"Madison"},{"ismomawake":0,"name":"Mom"},{"isdadawake":0,"name":"Dad"}]

In Swift json will be of type [[String:Any]]?. That means you have an Array of Dictionarys. The error tells you can't subscript an array with a String. That means that you need to loop through your son Array to do the code you want to:

 do{
        let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary

if let json as? [[String: Any]]{
for arrayJSONObj in json {


            isethanawake = arrayJSONObj["isethanawake"] as? Int ?? 0

            ismadisonawake = arrayJSONObj["ismadisonawake"] as? Int ?? 0

            ismomawake = arrayJSONObj["ismomawake"] as? Int ?? 0

            isdadawake = arrayJSONObj["isdadawake"] as? Int ?? 0

}
}
        print("hello" + String(isethanawake))
    }catch{
        print(error)
    }

I also do recommend using default values to your values (these two ??) instead of force unwrapping them to prevent your app from crashing.