请问怎么访问NSDictionary的内容

在访问字典内容的时候失败：
`NSLog(@"self.userCommentsArray %@",self.userCommentsArray);返回null。
`

请帮忙：

NSData *jsonData = [NSData dataWithContentsOfURL:myURL];
NSDictionary *userCommentsDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
    NSLog(@"userCommentsDictionary %@",userCommentsDictionary); // this works
    self.userCommentsArray = [[userCommentsDictionary objectForKey:@"from"] objectForKey:@"name"];
    NSLog(@"self.userCommentsArray %@",self.userCommentsArray); 

这是dicitionary的NSlog输出：

userCommentsDictionary {
        data =     (
                    {
                created = "2013-07-16T18:42:56+02:00";
                from =             {
                    id = 27;
                    name = "user-4";
                };
                id = 2553;
                message = "liquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
            },
                    {
                created = "2013-07-16T18:42:56+02:00";
                from =             {
                    id = 28;
                    name = "user-5";
                };
                id = 2554;
                message = "x ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
            },
                    {
                created = "2013-07-19T16:18:56+02:00";
                from =             {
                    id = 24;
                    name = "user-1";
                };
                id = 5125;
                message = test comment;
            },
                    {
                created = "2013-07-19T17:00:21+02:00";
                from =             {
                    id = 24;
                    name = "user-1";
                };
                id = 5126;
                message = "test comment ";
       }
        );
        meta =     {
            totalCount = 18;
        };
    }