Issues Accessing "dailysummary" section of Wunderground API

Question

I have a group of functions that are created to retrieve data from the Wunderground API. However, because of the fact that the "dailysummary" section is enclosed in an array somehow, I cannot figure out how to access it. This is the part that I cannot access:

"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" }
    ]
}

See this site for reference on how I call the API: http://devdactic.com/rest-api-parse-json-swift/

Answer 1

You might be using SwiftyJSON or another library, but for my example I'm doing it just with NSJSONSerialization.

Here I get into the "history" dictionary then into the "dailysummary" dictionary and I cast the result as an array of dictionaries (let's say your JSON dictionary is named "json" too):

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
    }
}

Then I loop inside the array (in your example there's only one object inside but there could be many): some values are strings, other are dictionaries, like "date".

I'm using "if let" to safely unwrap and cast the contents:

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"
            }
        }
    }
}

If you're using SwiftyJSON or equivalent, you won't have to do the casts manually, but you'll have to use the library specific syntax, maybe something in this style:

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