var Rating = self.currentPerson.Rating
let c = Rating - 1
Im trying to get the value x of self.currentPerson.Rating and subtract 1 from value x. But Im only getting the error bellow.
Error : Binary operator '-' cannot be applied to operands of type
'NSNumber' and 'Int'
Question : How do I solve this?
Thanks
Problem solved.
By simply adding .intValue.
var Rating = self.currentPerson.Rating
let c = Rating.intValue - 1
Cred #luk2302
Related
I am trying to convert my current project to Swift 3 and am running into problems regarding the objectForKey to objectFor conversion.
The type of myData is AnyObject
Before:
let x = myData.objectForKey('myKey')
Now:
let x = myData.objectFor('myKey') // not working.
In the second case, XCode gives me error Cannot call value of non-function type '((AnyObject) -> AnyObject?)!' which I have no idea how to fix.
Does anyone know how to updated the objectForKey method and why this conversion is not working?
Other Example:
I created another example in a playground to reproduce this issue. The lines of code used are pasted below. The outcome of running this is the same error as stated above.
var x: AnyObject = ["Hello" : "Goodbye"] as AnyObject
x.objectFor("Hello")
The syntax has changed from:
let x = myData.objectForKey("myKey")
to:
let x = myData.object(forKey:"myKey")
in Swift 3.
Example:
var x : AnyObject = ["Hello" : "Goodbye"] as AnyObject
x.object(forKey:"Hello")
I'm using Xcode 7.3.1 and Swift, and i'm trying to set a random number between 1 and 50 like that: variableName = random()%50
Then i have to move an ImageView in the Y axe of that random value:
imageviewName.center.y = imageviewName.center.y - variableName
But it gives me the following error: "cannot convert value of type 'int' to expected argument type 'CGFloat'.
So I declared the variable like that:
var RandomSquirrel2 = CGFloat() but it still doesn't wok.
How can I generate a random number in Swift?
You need to covert the Int to CGFloat
imageviewName.center.y = imageviewName.center.y - CGFloat(variableName)
You need to cast variableName to CGFloat. because random() returns an Int and not A CGFloat.
imageviewName.center.y = imageviewName.center.y - CGFloat(variableName)
I am trying to generate a random number in Swift:
var amountOfQuestions = 2
var randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1
but this results in the error:
Cannot convert value of type 'Int' to expected argument type 'UInt32'
What is the problem? Any ideas on what I can do to fix this error?
Declare amountOfQuestions as a UInt32:
var amountOfQuestions: UInt32 = 2
PS: If you want to be grammatically correct it's number of questions.
First thing:
The method "arc4random_uniform" expects an argument of type UInt32, so when you put that subtraction there, it converted the '1' you wrote to UInt32.
Second thing: In swift you can't subtract a UInt32 (the '1' in your formula) from an Int (in this case 'amountOfQuestions').
To solve it all, you'll have to consider changing the declaration of 'amountOfQuestions' to:
var amountOfQuestions = UInt32(2)
That should do the trick :)
Make your amountOfQuestions variable an UInt32 rather than an Int inferred by the compiler.
var amountOfQuestions: UInt32 = 2
// ...
var randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1
arc4random_uniform requires a UInt32.
From the Darwin docs:
arc4random_uniform(u_int32_t upper_bound);
I have converted a String to an Int by by using toInt(). I then tried multiplying it by 0.01, but I get an error that says Could not find an overload for '*' that accepts the supplied argument. Here is my code:
var str: Int = 0
var pennyCount = 0.00
str = pennyTextField.text.toInt()!
pennyCount = str * 0.01
From reading other posts it seems that the answer has to do with the type. For example if the type is set as an Integer then it gets a similar error. I have tried changing the type to an Int, but that doesn't seem to solve the problem.
I have also tried setting the type for 'str' and 'pennyCount' as Floats and Doubles and all combinations of Floats, Doubles, and Ints. My guess is the the problem has to do with toInt() function's conversion of a String to an Integer.
Could someone help clarify what the issue may be?
Swift seems to be fairly picky about implied type casting, so in your example you're multiplying str (an Integer) by 0.01 (a Double) so to resolve the error, you'll need to cast it like this:
var str: Int = 0
var pennyCount = 0.00
str = pennyTextField.text.toInt()!
pennyCount = Double(str) * 0.01
For example, I have the following code:
let numberOfBlocks = 3
let blockWidth = SKSpriteNode(imageNamed: "image.png").size.width
let padding = 20.0
let offsetX : Float = (self.frame.size.width - (blockWidth * numberOfBlocks + padding * (numberOfBlocks-1))) / 2
I got the error:
'Double' is not convertible to 'UInt8'
Is there a way to implicitly convert the data type (maybe only for primitive data type)?
Edit:
I know how to do the explicit conversion by using constructor of particular type as Iducool suggested. But it's not a big help to my question because we even don't know where to add the conversions. I simplified my expression in playground:
The problem is in "padding" variable, the error message is
'Double' is not convertible to 'UInt8'.
So I did the conversion:
Then the problem is in "blockWidth" variable now.
I added the conversion again:
And error message is:
Type 'UInt8' does not conform to protocol 'FloatLiteralCovertible'
The final working expression is:
Is it simple and swift? I don't think so.
There is no implicitly cast in Swift.
Easy way of conversion in swift is using constructor of particular type.
Like if you want to get Float from double then you can use Float(doubleValue) and Same way if you want to convert float to integer then you can use Int(floatValue).
In your case:
let intValue = UInt8(doubleValue)
Beware that you will lose any value after the decimal point. So, choose a better way. Above conversion is just to help you in understanding.
Note that Swift always chooses Double (rather than Float) when inferring the type of floating-point numbers.
Swift doesn't support implicitly cast anymore in Xcode6 GM. Following answer only apply to Xcode6 beta version.
I don't want to talk about implicitly cast is good or bad, but you can have it if you really want with __conversion()
e.g. If you need UInt8 and Int be able to convert from Double
extension Double {
func __conversion() -> UInt8 { return UInt8(self) }
func __conversion() -> Int { return Int(self) }
// add more if you need to
}
xcrun swift
Welcome to Swift! Type :help for assistance.
1> extension Double {
2. func __conversion() -> UInt8 { return UInt8(self) }
3. }
4> var d = 1.0
d: Double = 1
5> var u8 : UInt8 = d
u8: UInt8 = 1
6>
Note: I won't put this in my production code. I only want to point out it if possible but not recommending it.
using bridgeToObjectiveC() method you can call the methods provided in Objective - C to convert from one primitive data type to another for e.g.
variable_name.bridgeToObjectiveC().intValue
will convert that variable named variable_name to integer
Implicit conversion is possible but with literals only and some conversions are available from the box e.g. Int -> Double:
let a = 3 // Int
let b = 100.5 // Double
// Doesn't work with variables
let c = a * b // Error: Binary operator '*' cannot be applied to operands of type 'Int' and 'Double'
// But this works, because Int(3) literal converts to Double(3.0) implicitly
let d = 3 * b // 301.5
If you want to make backward conversion Double -> Int you should extend Int with ExpressibleByFloatLiteral:
extension Int: ExpressibleByFloatLiteral {
public init(floatLiteral value: Double) {
self.init(value)
}
}
// Double(100.5) converts to Int(100)
let e = a * 100.5 // 300
Even more it's possible to implicitly convert to any type from literals, for instance String -> URLRequest:
extension URLRequest: ExpressibleByStringLiteral {
public init(stringLiteral value: String) {
self.init(url: URL(string: value)!)
}
}
let request: URLRequest = "https://www.google.com"