访问Wunderground“每日摘要”部分的问题

Question

我有一组函数，创建这些函数是为了从Wunderground中检索数据。但是，由于“每日摘要”部分以某种方式包含在数组中，所以我不知道如何访问它。这是我无法进入的部分：

"history": {
    "dailysummary": [
     { "date": {
     "pretty": "12:00 PM PDT on August 12, 2015",
    "year": "2015",
    "mon": "08",
    "mday": "12",
    "hour": "12",
    "min": "00",
    "tzname": "America/Los_Angeles"
    },
    "fog":"0","rain":"0","snow":"0","snowfallm":"0.00","snowfalli":"0.00","monthtodatesnowfallm":"", "monthtodatesnowfalli":"","since1julsnowfallm":"", "since1julsnowfalli":"","snowdepthm":"", "snowdepthi":"","hail":"0","thunder":"0","tornado":"0","meantempm":"26", "meantempi":"79","meandewptm":"16", "meandewpti":"60","meanpressurem":"1014", "meanpressurei":"29.94","meanwindspdm":"9", "meanwindspdi":"5","meanwdire":"","meanwdird":"331","meanvism":"16", "meanvisi":"10","humidity":"","maxtempm":"33", "maxtempi":"91","mintempm":"19", "mintempi":"66","maxhumidity":"78","minhumidity":"34","maxdewptm":"17", "maxdewpti":"62","mindewptm":"15", "mindewpti":"59","maxpressurem":"1016", "maxpressurei":"30.01","minpressurem":"1012", "minpressurei":"29.88","maxwspdm":"24", "maxwspdi":"15","minwspdm":"0", "minwspdi":"0","maxvism":"16", "maxvisi":"10","minvism":"16", "minvisi":"10","gdegreedays":"28","heatingdegreedays":"0","coolingdegreedays":"14","precipm":"0.00", "precipi":"0.00","precipsource":"","heatingdegreedaysnormal":"0","monthtodateheatingdegreedays":"0","monthtodateheatingdegreedaysnormal":"0","since1sepheatingdegreedays":"","since1sepheatingdegreedaysnormal":"","since1julheatingdegreedays":"0","since1julheatingdegreedaysnormal":"17","coolingdegreedaysnormal":"5","monthtodatecoolingdegreedays":"106","monthtodatecoolingdegreedaysnormal":"69","since1sepcoolingdegreedays":"","since1sepcoolingdegreedaysnormal":"","since1jancoolingdegreedays":"600","since1jancoolingdegreedaysnormal":"280" }
    ]
}

有关如何调用API：http://devdactic.com/rest-api-parse-json-swift/的参考信息，请参阅本网站。

Answer 1

您可能正在使用SwiftyJSON或其他库，但在我的示例中，我只使用NSJSONSerialization。

在这里，我进入“历史”字典，然后进入“每日摘要”字典，并将结果转换为一系列字典(假设您的JSON字典也被命名为"json“)：

if let json = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &err) as? [String:AnyObject] {
    if let history = json["history"] as? [String:AnyObject],
        let daily = history["dailysummary"] as? [[NSObject:AnyObject]] {
        // "daily" is our array
    }
}

然后，我在数组中循环(在您的示例中，其中只有一个对象，但可能有很多)：一些值是字符串，另一些值是字典，比如“日期”。

我使用"if let“来安全地打开和抛出内容：

if let json = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &err) as? [String:AnyObject] {
    if let history = json["history"] as? [String:AnyObject],
        let daily = history["dailysummary"] as? [[NSObject:AnyObject]] {
        for item in daily {
            for (key, _) in item {
                println(key) // "mintempm", "mindewpti", "since1sepheatingdegreedaysnormal", "meantempm", etc
            }
            if let coolingdegreedaysnormal = item["coolingdegreedaysnormal"] as? String {
                println(coolingdegreedaysnormal) // "5"
            }
            if let date = item["date"] as? [String:AnyObject], let pretty = date["pretty"] as? String  {
                println(pretty) // "12:00 PM PDT on August 12, 2015"
            }
        }
    }
}

如果您使用的是SwiftyJSON或等效文件，则不需要手动进行转换，但您必须使用库特定的语法，可能需要使用这种样式的转换：

for item in json["history"]["dailysummary"].array {
    // ...
}