ios - 统计某个对象在 JSON 查询中出现的次数

Question

我返回的 JSON 具有如下所示的粗略结构，我试图弄清楚如何计算有多少个平台(在本例中为三个，但可以是 1 到 20 或所以)。我已将 JSON 返回到 NSDictionary 中，并使用诸如此类的行来检索我需要的数据:

_firstLabel.text = _gameDetailDictionary[@"results"][@"name"];

在上述情况下，它将从 results 部分获取 name。由于有多个平台，我需要构建一个循环来循环遍历 platforms 部分中的每个 name。不太确定该怎么做。感谢所有帮助!

"results":{
    "platforms":[
        {
            "api_detail_url":"http://",
            "site_detail_url":"http://",
            "id":18,
            "name":"First Name"
        },
        {
            "api_detail_url":"http://",
            "site_detail_url":"http://",
            "id":116,
            "name":"Second Name"
        },
        {
            "api_detail_url":"http://",
            "site_detail_url":"http://",
            "id":22,
            "name":"Third Name"
        }
    ],

编辑:这是我的 fetchJSON 方法:

- (NSDictionary *) fetchJSONDetail: (NSString *) detailGBID {

    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible: YES];

    NSString *preparedDetailURLString = [NSString stringWithFormat:@"http://whatever/format=json", detailGBID];
    NSLog(@"Doing a detailed search for game ID %@", detailGBID);

    NSData *jsonData = [NSData dataWithContentsOfURL: [NSURL URLWithString:preparedDetailURLString]];

    _resultsOfSearch = [[NSDictionary alloc] init];
    if (jsonData) {
        _resultsOfSearch = [NSJSONSerialization JSONObjectWithData: jsonData
                                                           options: NSJSONReadingMutableContainers
                                                             error: nil];
    }

    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible: NO];

    NSString *results = _resultsOfSearch[@"number_of_page_results"];
    _numberOfSearchResults = [results intValue];

    NSArray *platforms = [_resultsOfSearch valueForKey:@"platforms"];
    int platformsCount = [platforms count];
    NSLog(@"This game has %d platforms!", platformsCount);

    return _resultsOfSearch;

Answer 1

“平台”JSON 字段是一个数组，因此假设您已经使用类似的方式对 JSON 进行了反序列化，

NSMutableDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:resultsData options:NSJSONReadingMutableContainers error:&error];

然后，您可以将平台分配给 NSArray，

NSDictionary *results = [responseJSON valueForKey:@"results"];

NSArray *platforms = [results valueForKey:@"platforms"];

...并找到平台数量，

int platformsCount = [platforms count];

在您的情况下，如果您想遍历平台，您可以使用，

for (NSDictionary *platform in platforms)
{
    // do something for each platform
}