After convert JSON array to NSDictionary, what should I do? - ios

Question

I need to parse a JSON array in the following format:
[
{
name: "10-701 machine learning",
_id: "52537480b97d2d9117000001",
__v: 0,
ctime: "2013-10-08T02:57:04.977Z"
},
{
name: "15-213 computer systems",
_id: "525616b7807f01fa17000001",
__v: 0,
ctime: "2013-10-10T02:53:43.776Z"
}
]
So after getting the NSData, I transfer it to a NSDictionary:
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSLog(#"%#", dict);
But viewing from the console, I think the dictionary is actually like this:
(
{
"__v" = 0;
"_id" = 52537480b97d2d9117000001;
ctime = "2013-10-08T02:57:04.977Z";
name = "10-701 machine learning";
},
{
"__v" = 0;
"_id" = 525616b7807f01fa17000001;
ctime = "2013-10-10T02:53:43.776Z";
name = "15-213 computer systems";
}
)
What do those parenthesis in the outside mean? How should I further transfer this NSDictionary to an NSArray or an NSMutableArray of some Course objects (what I defined myself, try to represent each element of the JSON array)?

Answer 1

Use this code,
NSArray *array = [NSJSONSerialization JSONObjectWithData: responseData options:NSJSONReadingMutableContainers error:&error];
NSDictionary *dict = [array objectAtIndex:0];
Then you can retrieve the values by following code,
NSString *v = [dict objectForKey:#"__v"];
NSString *id = [dict objectForKey:#"_id"];
NSString *ctime = [dict objectForKey:#"ctime"];
NSString *name = [dict objectForKey:#"name"];

Answer 2

The parenthesis are just the result of NSDictionary output format not being exactly the same thing as how JSON is formatted. Your code still successfully converted the JSON into a NSDictionary object.
I think what you really want, though, is an array of dictionaries. Something like this:
NSArray *json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSDictionary *firstObject = [json objectAtIndex:0];
After this, firstObject would contain:
{
"__v" = 0;
"_id" = 52537480b97d2d9117000001;
"ctime" = "2013-10-08T02:57:04.977Z";
"name" = "10-701 machine learning";
}
And you can retrieve the information with objectForKey:
NSString *time = [firstObject objectForKey:#"ctime"];
// time = "2013-10-08T02:57:04.977Z"
Hope that helps.