I am trying to convert my project to Swift 3.0 however I am having two error messages when working with NSNumber
and Integers
.
Cannot assign type int to type NSNumber
for
//item is a NSManaged object with a property called index of type NSNumber var currentIndex = 0 for item in self.selectedObject.arrayOfItems { item.index = currentIndex currentIndex += 1 }
and even when I change currentIndex
to a type NSNumber
then I get the error
Binary operator '+=' cannot be applied to type 'NSNumber' and 'Int'
so then I create a property called one
of type NSNumber
to add to currentIndex
but then get the following error;
Binary operator '+=' cannot be applied to two NSNumber operands
&& the second error I get is
No '+' candidates produce the expected contextual result type NSNumber
let num: Int = 210 let num2: Int = item.points.intValue item.points = num + num2
Here I am just trying to add 210 to the points property value, item
is a NSManagedObject
.
So basically I am having issues getting my head around adding numbers to properties of type NSNumber
. I am working with NSNumber
because they are properties of NSManagedObject
's.
Can anyone help me out ? I have over 80 errors which are all either one of the above errors mentioned.
Thanks
The purpose of NSNumber is simply to box primitive types in objects (pointer types), so you can use them in situations that require pointer-type values to work. One common example: you have to use NSNumber if you want to persist numeric values in Core Data entities.
Overview. NSNumber is a subclass of NSValue that offers a value as any C scalar (numeric) type. It defines a set of methods specifically for setting and accessing the value as a signed or unsigned char , short int , int , long int , long long int , float , or double or as a BOOL .
A static, plain-text Unicode string object that bridges to String ; use NSString when you need reference semantics or other Foundation-specific behavior.
Swift version: 5.6. A CGFloat is a specialized form of Float that holds either 32-bits of data or 64-bits of data depending on the platform. The CG tells you it's part of Core Graphics, and it's found throughout UIKit, Core Graphics, Sprite Kit and many other iOS libraries.
Before Swift 3, many types were automatically "bridged" to an instance of some NSObject
subclass where necessary, such as String
to NSString
, or Int
, Float
, ... to NSNumber
.
As of Swift 3 you have to make that conversion explicit:
var currentIndex = 0 for item in self.selectedFolder.arrayOfTasks { item.index = currentIndex as NSNumber // <-- currentIndex += 1 }
Alternatively, use the option "Use scalar properties for primitive data types" when creating the NSManagedObject
subclass, then the property has some integer type instead of NSNumber
, so that you can get and set it without conversion.
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