This will show the following error: 'JSValue' is not convertible to 'NSNumber'. If it's not possible to convert, how should I go about getting the JSValue and assigning it to my NSNumber variable?
var sentences:NSNumber = getSentences.callWithArguments([])
According to the header file JSValue.h, you need to call toNumber() on your JSValue object. So it's probably:
var sentences:NSNumber = getSentences.callWithArguments([]).toNumber()
You can try:
if let sentences = getSentences.callWithArguments([]) as? NSNumber {
// consume sentences here
}
The if let structure is probably the simplest access to it since it may not actually BE a number, If that doesn't work, you'll have to go back to JavaScriptCore and call JSValueToNumber:
let sentences = getSentences.callWithArguments([])
let nSentences = JSValueToNumber(context, sentences, nil)
Related
I have been trying to parse a CSV file forever and I am almost there. I have gotten it to a multi-dimensional array of strings using this code:
let path = Bundle.main.url(forResource: "BaseballSimStats", withExtension: "csv")
var file = String()
do {
file = try String(contentsOf: path!)
print(file)
} catch {
print(error)
}
let stringarray = file.components(separatedBy: "\n").map{ $0.components(separatedBy: ",") }
Now the last step is to turn it into a Double. I am using this code:
probs = Double[[stringarray]]
I get an error saying that the type has no subscript errors. I get rid of the subscript references and the error goes away. Why is this error here and how can I get rid of it? Thanks!
I used .map() to map the String into a Double, this should work for nested array
var strArray = [["1.00000","1.10000"],["2.00000","2.10000"]]
var doubleArray = strArray.map { (arr: Array) -> Array<Any> in
return arr.map({ (value: String) -> Double in
return Double(value)!
})
}
print(strArray)
print(doubleArray)
I am not sure if the double map was needed.
I am not a swift guru but this code should help you achieve what you want..
I'm not familiar with Double[[stringarray]] syntax so I don't know how that's supposed to work. I do know you can't just cast between array types.
The simplest way is probably to wrap the innermost call with Double.init():
file.components(separatedBy: "\n").map{ $0.components(separatedBy: ",").map { Double($0)! }}
Of course, there's a bit more to CSV than just splitting on commas and assuming everything is a valid number, so I'd highly recommend using an existing CSV parsing library for any real data.
I'm comparing the characters contained within two words. In seeking to accomplish this, Set (aka NSSet) seemed like the way to go to accomplish this task. I've discovered it returns false positives on matches, so I am attempting to use CountedSet (aka NSCountedSet) instead.
I'm able to initialize a Set without issue, but I can't get the CountedSet initializer to work. Here's what I've done...
I start with a String:
// Let's say myTextField.text = "test"
let textFieldCharacters = myTextField.text?.characters
// word is a string from the ENABLE list of words
let wordCharacters = word.characters
Then I dump the characters into an Array:
var wordCharactersArray = [Character]()
for character in wordCharacters {
wordCharacterArray.append(character)
}
var textFieldCharactersArray = [Character]()
for character in textFieldCharacters {
wordCharacterArray.append(character)
}
Then I create a Set from the character arrays:
let textFieldSet = Set<Character>(textFieldCharactersArray)
let wordSet = Set<Character>(wordCharactersArray)
Finally, I test to see if the textFieldSet is a superSet of wordSet with the following:
textFieldSet.isSuperset(of: wordSet)
Going back to my example, if myTextField.text is "test", I'm returning values for word whose characters are a superset of the wordSet, but the counts of the individual elements don't match the character counts of myTextField.text
In researching my issue, I've found CountedSet (fka NSCountedSet), which I think would resolve my issue. It has two method signatures:
public convenience init(array: [AnyObject])
public convenience init(set: Set<NSObject>)
I've tried initializing the 2 sets of characters like so:
let textFieldSet = CountedSet(array: textFieldCharacterArray)
let wordSet = CountedSet(array: wordCharacterArray)
I get the following error for the sets
Cannot convert value of type '[Character]' to expected argument type
'[AnyObject]'.
So I tried initializing the set like this:
let textFieldSet = CountedSet(array: textFieldCharacterArray as! [AnyObject])
Which yields the following error:
'AnyObject' is not a subtype of 'Character'
I've also tried to initialize the CountedSet with a Set, per the method signature, but I get errors when I try to do that, too.
Any suggestions how to initialize a CountedSet would be greatly appreciated.
You are correct that if you need to compare not just the presents of elements but also their count, you should use CountedSet, which is a renaming of NSCountedSet for swift 3.0. The problem you are running into is CountedSet can only accept elements that are objects and Characters are not. As Eric D points out in their comment, the easies way to get around this is by mapping your [Character] to [String] which will bridge to [NSString].
You are not running into this problem using Set, because it is a native Swift collection type that initialize with elements of any type. This is why you can initialize a Set with [Character].
To see the difference:
let word = "helo"
let wordCharacters = Array(word.characters)
let wordSet = Set(wordCharacters)
let wordCharStrings = wordCharacters.map{String($0)}
let wordCountedSet = CountedSet(array: wordCharStrings)
let textField = "hello"
let textFieldCharacters = Array(textField.characters)
let textSet = Set(textFieldCharacters)
let textFieldCharStrings = textFieldCharacters.map{String($0)}
let textFieldCountedSet = CountedSet(array: textFieldCharStrings)
textFieldCountedSet.isSubset(of: wordCountedSet as! Set<NSObject>) // returns false, but if word had two or more l's it would return true
textSet.isSubset(of: wordSet) // returns true
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 currently trying to get a value called "loot" out of the current user. I need the value as a String, but Swift is being stubborn and says it "cannot convert Anyobject to String". The Parse documentation for iOS says to use something like:
let score = gameScore["score"] as String
and so, I try this :
let lootAmount = user["loot"] as String
BTW 'user' is referring to the current user. When I try that, it gives error saying it's not convertible. I tried placing '!'s and '?'s wherever Xcode suggested, but it just crashed the app with no error.
So, how do I get the user value called "loot" as a String?
Loot is an NSNumber not an NSString or String.
You could convert it to a String like this:
if let loot = user["loot"] as? NSNumber {
let lootString = "\(loot)"
}
If you're not sure of an object's type, you can ask it using dynamicType:
print(user["loot"]!.dynamicType)
//prints `__NSCFNumber.Type`
You may need to downcast AnyObject. Try this: let lootAmount = user["loot"] as? String or unwrap your optional user if you haven't done so:
let currentUser = PFUser.currentUser()
if let user = currentUser {
let lootAmount = user["loot"] as String
}
let dataStr = data.base64EncodedStringWithOptions(options: Encoding64CharacterLineLength)
Doesn't compile with "Use of unresolved identifier 'Encoding64CharacterLineLength'"
When I just change the param to zero with
let dataStr = data.base64EncodedStringWithOptions(options: 0)
It gives even stranger error: "Cannot convert the expression of type 'String!' to type 'String!'" I found a way to init NSString with NSData (however, I still can't get the difference between String and NSString), but I'm really curious why these two lines of code don't work.
Unless explicitly given an external name, first argument of a method in Swift is not a named argument. Therefore you should be doing: data.base64EncodedStringWithOptions(x) without the options: part.
If you actually look at the argument type, NSDataBase64EncodingOptions, you'll notice that it is a struct conforming to RawOptionSet with static variables for option constants. Therefore to use them you should do: NSDataBase64EncodingOptions.Encoding64CharacterLineLength
The NSDataBase64EncodingOptions struct (or RawOptionSet in general) is also not convertible from integer literals (like 0). But it does conform to NilLiteralConvertible so if you don't want any options you can pass nil.
Putting it together:
let dataStr = data.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
or
let dataStr = data.base64EncodedStringWithOptions(nil)
Swift3.0
let dataStr = data.base64EncodedString(options: [])
For Swift 2.x use an array for options:
let dataStr = data.base64EncodedStringWithOptions([.Encoding64CharacterLineLength])
let dataStr = data.base64EncodedStringWithOptions([])
For swift 3.0+ use this ,
var dataStr = data.base64EncodedString(options: .lineLength64Characters)
Swift 3.x
let fileStream = fileData?.base64EncodedString(options: NSData.Base64EncodingOptions.init(rawValue: 0))
You don't have to put in the "options:" identifier in the argument. You DO have to specify that Encoding64CharacterLineLength is a static member of NSDataBase64EncodingOptions, like so:
var dataStr = data.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
let dataStr = data.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.allZeros)
Since the default parameter value is set be an empty array…
/// Returns a Base-64 encoded string.
///
/// - parameter options: The options to use for the encoding. Default value is `[]`.
/// - returns: The Base-64 encoded string.
#inlinable public func base64EncodedString(options: Data.Base64EncodingOptions = []) -> String
you just need to call
let dataStr = data.base64EncodedString()