How to convert UInt to Int in swift?

Question

I need to convert a variable from NSUInt to Int to pass it as argument to allocate.

I tried initializing with Int() but the compiler refuses cannot invoke initializer for type 'int' with an argument of type '(UInt?)'

this is the variable: NSUInteger count this is the call to allocatelet outPut = UnsafeMutablePointer<Float>.allocate(capacity: count)

Without the conversion the compiler generates this error: cannot convert value of type 'UInt?' to expected argument type 'Int'

Joakim Danielson · Accepted Answer · 2019-09-25T12:24:06.597

2

It's because it is optional, you need to unwrap it

var x: UInt?

if let z = x {
    let y = Int(exactly: z) 
}

Note that Int(exactly:) returns an optional as well so you might want to use a guard statement or another if let...

Update, as pointed out by vacawama Int(z) might crash

edited Sep 25 '19 at 12:24

answered Sep 25 '19 at 12:04

Joakim Danielson

This will crash if `x` is too big for an `Int`. I recommend `if let z = x, let y = Int(exactly: z) {` – vacawama Sep 25 '19 at 12:16

score 0 · Answer 2 · answered Sep 25 '19 at 12:01

0

You need to use bit pattern initialiser.

let unsignedInt = Int(bitPattern: UInt)

But this will not take care overflow situations.

answered Sep 25 '19 at 12:01

Shreeram Bhat

2 Answers2