New to swift, just trying to catch some data.
so here is my swift code i used
let url = Bundle.main.url(forResource: "kurdiebg", withExtension: "plist")!
do {
let data = try Data(contentsOf: url)
let dataArray = try PropertyListSerialization.propertyList(from: data, format: nil) as! [[String:String]]
// Bloody Error is this
let request = dataArray(value(forKey: "Key"))
print(dataArray.count)
} catch {
print("This error must not happen", error)
}
i am getting
Cannot call value of non-function type '[[String : String]]'
what exactly i am trying to do?
so i have this plist file and i want to allow users to search in it , i perform this via a button action with this code above, so if a user write abbey, it would get the kurdi meaning,
The error occurs because you are using wrong syntax.
dataArray is not a function, you probably mean
dataArray.value(forKey: "Key")
However using KVC methods like value(forKey is only useful if you know what KVC is and why you need KVC. In this case it's inappropriate.
dataArray – as the name implies – is an array which is subscripted by index so you can get for example the value for key english of the first item with
dataArray[0]["english"]
which is a synonym for
dataArray[0].object(forKey:"english")
Or if you want to find an item for a specific key
dataArray.first(where: { $0["english"] == "abbey"})
Related
In Swift, to retrieve an array from Firestore I use:
currentDocument.getDocument { (document, error) in
if let document = document, document.exists {
let people = document.data()!["people"]
print(people!)
} else {
print("Document does not exist")
}
}
And I receive data that looks like this
(
{
name = "Bob";
age = 24;
}
)
However, if I were to retrieve the name alone, normally I'd do print(document.data()!["people"][0]["name"]).
But the response I get is Value of type 'Any' has no subscripts
How do I access the name key inside that object inside the people array?
The value returned by document.data()!["people"] is of type Any and you can't access [0] on Any.
You'll first need to cast the result to an array, and then get the first item. While I'm not a Swift expert, it should be something like this:
let people = document.data()!["people"]! as [Any]
print(people[0])
A better way of writing #Frank van Puffelen's answer would be:
currentDocument.getDocument { document, error in
guard error == nil, let document = document, document.exists, let people = document.get("people") as? [Any] else { return }
print(people)
}
}
The second line may be a little long, but it guards against every error possible.
I can make a Facebook SDK Graph Request to get a user's likes, but I'm having trouble taking the returned values and storing one of the keys in an array of Strings. The request returns an NSDictionary of keys/values. Then, using objectForKey I can get the data key which returns what I want: the id and name of the "liked" page on Facebook.
Data returns elements like this:
{
id = 486379781543416;
name = "Star Wars Movies";
},
I specifically want only the "name" of all of these objects and to throw them into an array [String]. I tried to loop through the objects but I'm getting error ambiguous use of subscript. Here's the relevant code:
request.startWithCompletionHandler{(connection:FBSDKGraphRequestConnection!, result:AnyObject!, error:NSError!) -> Void in
let resultdict = result as! NSDictionary
let likes = resultdict.objectForKey("data") as! NSArray
print("Found \(likes.count) likes")
print(likes)
for object in likes{
let name = object["name"] as! String //error: ambiguous use of subsript
print(name)
}
}
After doing some research it looks like the issue is with the NSArray and that I should instead use Swift data types. I tried casting it to a Swift array but I got different errors.
What's the best way to handle this error?
Thanks!
update: Here is what the facebook API request returns:
{
data = (
{
id = 111276025563005;
name = "Star Wars (film)";
},
{
id = 115061321839188;
name = "Return of the Jedi";
}
);
paging = {
cursors = {
after = MTE1MDYxMzIxODM5MTg4;
before = Mjc0NzYzODk2MTg4NjY5;
};
next = "https://graph.facebook.com/v2.5/10155262562690368/likes?access_token=<redacted>";
};
}
You should always use the native Swift collection types wherever possible as NSArray and NSDictionary are really type-inspecific, and therefore can easily trigger "ambiguous use of subscript" errors.
You'll also want to avoid force down-casting, in case you receive data that's in the wrong format, or no data at all. This situation would be more elegantly handled with a guard, in order to prevent a crash. If your program depends on the force down-casting succeeding, and therefore should crash – then you can always call fatalError in the guard, with a descriptive error message in order to assist you in debugging the problem.
If I understand your data structure correctly, the request returns an AnyObject that should be a [String:AnyObject] (A dictionary of strings to any objects). In the case of the "data" key, the AnyObject value is then a [[String:AnyObject]] (An array of dictionaries of strings to any objects).
Therefore you'll want to do your casting in two stages. First, using a conditional downcast on your result to cast it as a [String:AnyObject]. If this fails, then the else clause of the guard will be executed and the code will return. You'll then want to get out your "data" value (your 'likes' array), and conditionally downcast it to a [[String:AnyObject]]. Both of these statements will handle the possibility of resultDict or resultDict["data"] being nil.
guard let resultDict = result as? [String:AnyObject] else {return}
guard let likes = resultDict["data"] as? [[String:AnyObject]] else {return}
You can put whatever error handling logic you want in the brackets of these statements to handle cases in which the results dictionary doesn't exist, was the wrong format, or there wasn't a 'likes' array in it.
You can then get an array of 'like' names through using flatMap.
let likeNames = likes.flatMap{$0["name"] as? String}
This will create an array of the like names of each dictionary – if the like names don't exist or aren't strings, then they won't be added. Because the compiler knows for certain that likes is a [[String:AnyObject]] – there's no ambiguity in subscripting its elements.
If you want a more general approach such as you're doing in your question, you can use a guard statement within a for loop.
for object in likes {
guard let name = object["name"] as? String else {continue}
print(name)
}
Again, you can put whatever error handling you wish in the brackets of the guard.
I want to get result from json and save this result in NSUserDefault, after I want to use the json array saved in NSUserDefault to add multiple annotation on the MapKit.
Currently to get json result, I use this : ( Swift 2.x )
let defaults = NSUserDefaults.standardUserDefaults()
//Get user content//
let url = NSURL(string: "http://www.example.com/folder/coordonate.php")
let request = NSMutableURLRequest(URL: url!)
// modify the request as necessary, if necessary
let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
data, response, error in
if data == nil {
print("request failed \(error)")
return
}
do {
if let json = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
print(json)
// print : {tab = "[london,paris]";}
var test = json["tab"]
defaults.setObject(test, forKey: "annotation") as? NSArray
}
} catch {
print(error)
}
}
task.resume()
NSUserDefaults.standardUserDefaults().synchronize()
And to get the NSUserdefault in another view, I try this code :
let defaults = NSUserDefaults.standardUserDefaults()
let test = NSUserDefaults.standardUserDefaults().objectForKey("annotation") as! NSArray
map.addAnnotations(test as! [MKAnnotation])
print("We saved this data: \(test)")
//No print, error before
But I have an error when I try with this method.
Could not cast value of type '__NSCFString' (0x1971a3958) to 'NSArray' (0x1971a4308).
If the "tab" property JSON actually being returned is:
[london, paris]
Then the property is not an array. What you're looking for would be:
['london', 'paris']
But additionally I can tell you that even if the "tab" property is a properly formatted JSON array your code will fail when it attempts to convert it to [MKAnnotation] anyway. That's because iOS's JSON library does not know how to convert a generic NSArray into it's typed equivalent. The NSJSONSerialization documentation indicates all the types that JSON will convert to. Best case scenario the "tab" property is an array of items with the same structure as MKAnnotation and are being converted to an array of dictionaries that you will have to convert to MKAnnotation yourself. But the JSON provided currently evaluates as a string. With my suggested change it will instead evaluate to an array of strings- still not sufficient to create an MKAnnotation from.
Your JSON data has to be one of the valid NSUserDefault types (String, NSArray, NSDictionary, NSData).
The quickest fix would be to store the JSON in NSUserDefaults as the NSData that comes back from the server. Then deserialize the NSData on the reading of NSUserDefaults.
If storing a subset of the JSON from the server is really needed, I would use Dictionaries, Arrays and validate the data before storing it. As a general Swift rule, I avoid using NSDictionary and NSArray to ensure the types are what I expect and won't cause a runtime crash.
change your php code to
$results = Array("tab" => ["london","paris"]);
instead of
$results = Array("tab" => "[london,paris]");
p.s
if using php earlier than 5.5 (or 5.4 not quite remember) then use:
$results = Array("tab" => Array("london","paris"));
==========================
you are casting the setObject func to NSArray and not the test object
defaults.setObject(test, forKey: "annotation") as? NSArray
should be
if let arrayTest = test as? NSArray{
defaults.setObject(arrayTest, forKey: "annotation")
}
I'm creating an app that should retrieve some JSON from a database.
This is how my JSON looks:
[{"id":"1","longitude":"10","latitude":"10","visibility":"5","timestampAdded":"2015-10-01 15:01:39"},{"id":"2","longitude":"15","latitude":"15","visibility":"5","timestampAdded":"2015-10-01 15:06:25"}]
And this is the code i use:
if let jsonResult = JSON as? Array<Dictionary<String,String>> {
let longitudeValue = jsonResult[0]["longitude"]
let latitudeValue = jsonResult[0]["latitude"]
let visibilityValue = jsonResult[0]["visibility"]
print(longitudeValue!)
print(latitudeValue!)
print(visibilityValue!)
}
As you can see it only gets the first chunk from the JSON and if there are no JSON at all it will crash, but if i want it to count the amount and make an array out of it like this:
var longitudeArray = [10, 15]
var latitudeArray = [10, 15]
And so on...
I also need this to be apple watch compatible so i can't use SwiftyJSON.
What do i do? I really hope you can help me!
Thanks.
SOLVED!
Problems was solved by "Eric D."
This is the code:
do {
if let url = NSURL(string: "YOU URL HERE"),
let data = NSData(contentsOfURL: url),
let jsonResult = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [[String:AnyObject]] {
print(jsonResult)
let longitudeArray = jsonResult.flatMap { $0["longitude"] as? String }
let latitudeArray = jsonResult.flatMap { $0["latitude"] as? String }
print(longitudeArray)
print(latitudeArray)
}
} catch let error as NSError {
print(error.description)
}
Thank you soo much Eric!! :-)
You could use flatMap to get an array of your elements:
let longitudeArray = jsonResult.flatMap { $0["longitude"] as? String }
let latitudeArray = jsonResult.flatMap { $0["latitude"] as? String }
etc.
flatMap is like map but unwraps optionals, which is adequate because we need to safely cast the type of the object we get from each dictionary in the json array.
$0 represents the object in the current iteration of flatMap of the array it's applied to.
If you're currently using SwiftyJSON, then that would be:
let longitudeArray = jsonResult.flatMap { $1["longitude"].string }
let latitudeArray = jsonResult.flatMap { $1["latitude"].string }
because .string is SwiftyJSON's optional String value getter.
But as you said, you don't want to use it (anymore), so you need to use NSJSONSerialization to decode your JSON data, there's plenty of examples on the Web and on SO. Then you will be able to use my original answer.
You're already getting an array with all of the elements (not just the first one. you're simply only accessing the first one). jsonResult is an array of dictionaries. Each dictionary (in this case, based on the json you provided) contains these elements: id, longitude, latitude, visibility and timestampAdded. In order to access each of them, you can simply loop over jsonResult and access the i'th element (and not always the 0 element). This will also prevent the crash you're experiencing with the json is blank or invalid (since you'll only be going over the valid elements in jsonResult.
This will give you the flexibility to create the custom arrays you wish to create (in order to create an array of all of the longitudes, for example, you will simply add that element to the new array while looping over jsonResult). However, if you'd like to save yourself the trouble of manually building these arrays and assuming you have control over the json structure, I would recommend changing the received json to the relevant structure (a dictionary or arrays instead of an array of dictionaries), so it would better fit your needs and provide you the results in the relevant format right "out of the box".
I am using the VK SDK for iOS, and I need to take out the images URLs from JSON response from VK.
The response is look like this:
The actual response could be AnyObject OR String, and I only need the largest image URL (photo_1280) as string.
In the response comes 1-10 photos and which parameters I will need to change to get the particular photo like first or second and so on.
I'm using Swift in my project but can understand Objective-C.
JSON is just a format that lets you exchange information between languages (or objects).
You need to 'parse' the string into a JSON object. Its a little different for each language. For example on iOS I create my UI elements from a JSON file where I load the file and create a dictionary object from it. In your case you are doing it from a string. You need to turn that string into a valid object in your language. In Swift I prefer a Dictionary. So I use a typealias for that and cast the nsDictionary as that type of object.
Then to access objects, I access keys in the dictionary. In your case you would create a dictionary object too, and access the "attachments" object, which in your case is an array so you'll need to do extra processing on it to get each image (i.e. go through the array). This should get you going.
typealias Dict = Dictionary<String,AnyObject>
func loadDictionaryFromJSON(jsonString:String) -> Dict
{
var JSONData:NSData! = jsonString.dataUsingEncoding(NSUTF8StringEncoding)
var JSONError:NSError?
let swiftObject:AnyObject = NSJSONSerialization.JSONObjectWithData(JSONData, options: NSJSONReadingOptions.AllowFragments, error: &JSONError)!
if let nsDictionaryObject = swiftObject as? NSDictionary
{
if let dictionaryObject = nsDictionaryObject as Dictionary?
{
return dictionaryObject as Dict
}else
{
println("Error could not make dictionary from NSDictionary in \(self)")
}
}else
{
"Error could not make NSDictionary in \(self)"
}
println("Empty dictionary passed, fix it!")
return Dict()
}
Now to access things you just do
var objects:Dictionary<String,AnyObject> = loadDictionaryFromJSON("{"what":"ever"}")
var whatever = objects["what"]