Swift - Parse certain data - ios

Question

Need to extract the data of desc from the below API response. From that i need to extract every a and b, so that i can use that in for a math addition app.
data from the server
[
{
"id": 226,
"name": "chorename",
"desc": "{\n \"questions\" : [\n {\n \"b\" : 2,\n \"a\" : 1\n },\n {\n \"b\" : 3,\n \"a\" : 2\n },\n {\n \"b\" : 2,\n \"a\" : 8\n },\n {\n \"b\" : 9,\n \"a\" : 7\n },\n {\n \"b\" : 3,\n \"a\" : 6\n }\n ],\n \"operation\" : \"addition\"\n}",
"reward": "1.00",
"sched": "2018-04-19T15:54:24.657644+08:00",
"parent": "shit",
"type": "homework",
"child": "",
"occurrence": {
"name": "once"
},
"status": {
"name": "ongoing"
},
"date_created": "2018-04-23T14:16:35.739436+08:00",
"date_modified": "2018-04-23T14:16:35.790237+08:00"
}
]
code on getting request
func demoApi1() {
Alamofire.request("", method: .get, parameters: nil, encoding: JSONEncoding.default, headers: nil).responseJSON { (response:DataResponse<Any>) in
switch(response.result) {
case .success(_):
guard let json = response.result.value as! [[String:Any]]? else{ return}
print("Ang Response: , \(json)")
for item in json {
var a = self.getAllDetail.append(item )
print("shit:" , a)
// if let title = item["title"] as? String {
// self.titleArray.append(title)
// }
}
if !self.getAllDetail.isEmpty{
DispatchQueue.main.async {
}
}
break
case .failure(_):
print("Error")
break
}
}
}
let devices = assign "a" here
let randomIndex = Int(arc4random_uniform(UInt32(devices.count)))
let randomItem = devices[randomIndex]
print("random item:" ,randomItem)
let device2 = //assign "b" here
let randomIndex1 = Int(arc4random_uniform(UInt32(devices.count)))
let randomItem1 = device2[randomIndex]
API Response:
Ang Response [["status": {
name = ongoing;
}, "sched": 2018-04-10T14:22:00+08:00, "desc": asdasdasdsa, "id": 224, "reward": 1.00, "parent": das, "child": dasdas, "date_created": 2018-04-19T15:54:24.657644+08:00, "name": sad, "occurrence": {
name = once;
}, "type": , "date_modified": 2018-04-19T15:54:24.703520+08:00], ["status": {
name = ongoing;
}, "sched": 2018-04-19T15:54:24.657644+08:00, "desc": {
"questions" : [
{
"b" : 2,
"a" : 1
},
{
"b" : 3,
"a" : 2
},
{
"b" : 2,
"a" : 8
},
{
"b" : 9,
"a" : 7
},
{
"b" : 3,
"a" : 6
}
],
"operation" : "addition"
}, "id": 226, "reward": 1.00, "parent": shit, "child": , "date_created": 2018-04-23T14:16:35.739436+08:00, "name": chorename, "occurrence": {
name = once;
}, "type": homework, "date_modified": 2018-04-23T14:16:35.790237+08:00]]

Answer 1

The below code can be used to convert a json string from string to dictionary
Objective-c
+ (NSDictionary *)dictionaryFromJSONString:(NSString *)jsonString
{
// #"{\"2\":\"3\"}"
NSError *jsonError;
NSData *objectData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:objectData
options:NSJSONReadingMutableContainers
error:&jsonError];
return json;
}
SWIFT
func getDictionaryFromString(_ jsonString: String) -> [String:Any]? {
let objectData = jsonString.data(using: .utf8)
var dict: [String:Any]?
if objectData != nil {
do {
dict = try JSONSerialization.jsonObject(with: objectData!, options: .allowFragments) as? [String : Any]
} catch {
print("Error occured.")
}
}
return dict
}
Once the dictionary is created you can use access the value via the key.