从另一个 NSDictionary 中提取 NSDictionary

Question

我的应用程序有一个包含许多其他NSDictionary的NSDictionary。如果我打印出这本字典，它的内容如下：

oxip =     {
    created = "2014-02-10 14:42:59";
    lastMsgId = "";
    requestTime = "1.6434";
    response =         {
        code = 001;
        debug = "";
        message = success;
        request = getHierarchyByMarketType;
        text = "n";
        williamhill =             {
            class =                 {
                id = 1;
                maxRepDate = "2014-02-10";
                maxRepTime = "07:31:48";
                name = "UK Football";
                text = "n";
                type =                     (
                                            {
                        id = 2;
                        lastUpdateDate = "2013-12-26";
                        lastUpdateTime = "13:32:54";
                        market =                             (
                                                            {
                                betTillDate = "2014-02-15";
                                betTillTime = "15:00:00";
                                date = "2014-02-15";
                                id = 140780553;
                                lastUpdateDate = "2014-02-10";
                                lastUpdateTime = "14:09:13";
                                name = "Queen of the South v Dundee - Match Betting";
                                participant =                                     (
                                                                            {
                                        handicap = "";
                                        id = 496658381;
                                        lastUpdateDate = "2014-02-10";
                                        lastUpdateTime = "14:09:13";
                                        name = Dundee;
                                        odds = "11/8";
                                        oddsDecimal = "2.38";
                                        text = "nnnnnn";
                                    },
                                                                            {
                                        handicap = "";
                                        id = 496658380;
                                        lastUpdateDate = "2014-02-10";
                                        lastUpdateTime = "14:09:13";
                                        name = Draw;
                                        odds = "5/2";
                                        oddsDecimal = "3.50";
                                        text = "n";
                                    },
                                                                            {
                                        handicap = "";
                                        id = 496658379;
                                        lastUpdateDate = "2014-02-10";
                                        lastUpdateTime = "14:09:13";
                                        name = "Queen of the South";
                                        odds = "11/8";
                                        oddsDecimal = "2.38";
                                        text = "n";
                                    }
                                );
                                text = "n";
                                time = "15:00:00";
                            }

我的应用程序到达名为以下名称的NSDictionary的最佳方式是什么：

名称 = "南方女王 v 邓迪 - 比赛投注"

无需遍历每个单独的字典并找到其键对象？

Answer 1

您可以使用

valueForKeyPath。它接受一条路径，用点分隔。例：

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"https://dl.dropboxusercontent.com/u/1365846/21680479.json"]]
                                                     options:0
                                                       error:nil];
NSLog(@"%@", [dict valueForKeyPath:@"response.williamhill.class.type.market.name"]);

这取决于字典的表示形式。如果williamhill部分正在更改，那么它当然不起作用。

Answer 2

如果不遍历映射数据类型（在本例中为 NSDictionary），就无法获取映射数据类型中的引用。考虑这个问题的简化版本：你有一个包含 N 个元素的链表，并且您希望到达第 N 个元素。因为这是一个链表，所以你必须遍历所有其他 N-1 节点才能获得最后一个引用。

NSDictionary是基于哈希的数据类型，其中存储键和值。在您描述的情况下，您没有对嵌套对象（NSDictionary 本身）的引用，因此还必须遍历包含它的所有字典。

希望这有助于为您指明正确的方向。