Setting variable values via an IF statement in Swift

Question

I am new to Swift. I am generating a random number (0 or 1) using the following:

var locValueDeterminer = Int.random(in: 0...1)

Based on the output of this, I want to set a variable appropriately:

if locValueDeterminer = 0 {
    var loc1Value : NSNumber = 0.5
    var loc2Value : NSNumber = 1
}
else {
    var loc1Value : NSNumber = 0.0
    var loc2Value : NSNumber = 1
}

However this returns many errors. What would be the correct conditional statement to use here?

Thanks

Why use NSNumber? Use Double, or Int, or some other specific Swift type. — rmaddy
– rmaddy, Commented Dec 3, 2018 at 21:17

Niv · Accepted Answer · 2022-05-26 06:14:19Z

6

Instead of == you wrote = in your if statement, and by the way here's a shorter version of that code

let locValueDeterminer = Int.random(in: 0...1)
    
let loc1Value = locValueDeterminer == 0 ? 0.5 : 0.0
let loc2Value = 1.0

Asking what locValueDeterminer == 0 ? 0.5 : 0.0 means?-

it's equivalent to condition ? something : something else

So in a way it translates to:

if locValueDeterminer == 0{
   loc1Value = 0.5
}else{
   loc1Value = 0.0
}

edited May 26, 2022 at 6:14

answered Dec 3, 2018 at 21:34

Niv

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1 Comment

Code Different Over a year ago

It's called the ternary conditional operator and is available in many languages like C, Javascript, PHP. It's not unique to Swift

nebyark · Accepted Answer · 2023-10-11 17:32:42Z

3

Ternaries are nice but that may not always be what you want to use. You can declare a let without a value, and assign it within an if/else block.

let loc1Value: Double
let loc2Value: Double
if Int.random(in: 0...1) == 0 {
    loc1Value = 0.5
    loc2Value = 0.0
} else {
    loc1Value = 0.0
    loc2Value = 0.0
}

edited Oct 11, 2023 at 17:32

answered Dec 3, 2018 at 23:00

nebyark

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1 Comment

brotskydotcom Over a year ago

This answer is less specific to the OP's problem, but feels like a better answer to the OP's general question, extending it to let constants as well as vars.

Leo Dabus · Accepted Answer · 2018-12-03 21:47:55Z

1

If your intend is to generate a true/false random condition in Swift 4 you can simply use Bool's random method:

let loc1Value = Bool.random() ? 0.5 : 0

answered Dec 3, 2018 at 21:47

Leo Dabus

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