Is it possible to increment a NSNumber variable in iOS swift?

Question

I used core data in my iOS swift project and declared a variable as Int32, in the class file it was initialised to NSNumber and while I tried to increment the variable by creating a object for that class, it shows that Binary operator += cannot be applied on NSNumber's. Is it possible to increment the NSNumber or should I choose Int16 or Int64 to access the variable.

Bullhead

NSNumber objects are immutable. You need to create a new instance with a new value based on the original value. – Raji

Bold move by the person who down voted all of the answers. – Canaigre

Answer 1

Here's three different answers from succinct to verbose:

Given that NSNumbers are immutable, simply assign it a new value equal to what you want:

var num : NSNumber = NSNumber(integer: 1) // NSNumber of 1
num = num.integerValue + 1 // NSNumber of 2

Or you can assign it another way:

var num : NSNumber = NSNumber(integer: 1) // NSNumber of 1
num = NSNumber(integer: num.integerValue + 1) // NSNumber of 2

Or you can convert the NSNumber to an Int, increment the int, and reassign the NSNumber:

var num : NSNumber = NSNumber(integer: 1) // NSNumber of 1
var int : Int = Int(num)
int += 1
num = NSNumber(integer: int) // NSNumber of 2

Canaigre

All three answers worked correctly.. Thanks a lot for your answers. – Bullhead

Answer 2

var number = NSNumber(integer: 10)
number = number.integerValue + 1

Tarp

Answer 3

Use var. Because let means constants.

var mybalance = bankbalance as NSNumber

But NSNumber is a Object and mybalance.integerValue cannot be assigned.

if let bankbalance: AnyObject? = keystore.objectForKey("coinbalance"){
    let mybalance: NSNumber = bankbalance as NSNumber
    var b = mybalance.integerValue + 50;
}

Nuthouse

Answer 4

It is impossible to increment an NSNumber once the object is created. There is no API that allows that.

You have to recreate the NSNumber object with a new (incremented) value:

let number = NSNumber(int: 15)
let incrementedNumber = NSNumber(int: number.intValue + 1)

Bookrest