Converting Boolean value to Integer value in swift

Question

I was converting from swift 2 to swift 3. I noticed that I cannot convert a boolean value to integer value in swift 3 :\ .

let p1 = ("a" == "a") //true

print(true)           //"true\n"
print(p1)             //"true\n"

Int(true)             //1

Int(p1)               //error

For example these syntaxes worked fine in swift 2. But in swift 3, print(p1) yields an error.

The error is error: cannot invoke initializer for type 'Int' with an argument list of type '((Bool))'

I understand why the errors are happening. Can anyone explain what is the reason for this safety and how to convert from Bool to Int in swift 3?

Answer 1

EDIT - From conversations in the comments, it is becoming clearer that the second way of doing this below (Int.init overload) is more in the style of where Swift is headed.

Alternatively, if this were something you were doing a lot of in your app, you could create a protocol and extend each type you need to convert to Int with it.

extension Bool: IntValue {
    func intValue() -> Int {
        if self {
            return 1
        }
        return 0
    }
}

protocol IntValue {
    func intValue() -> Int
}

print("\(true.intValue())") //prints "1"

EDIT- To cover an example of the case mentioned by Rob Napier in the comments below, one could do something like this:

extension Int {
    init(_ bool:Bool) {
        self = bool ? 1 : 0
    }
}

let myBool = true
print("Integer value of \(myBool) is \(Int(myBool)).")

Answer 2

Tested in swift 3.2 and swift 4

There is not need to convert it into Int

Try this -

let p1 = ("a" == "a") //true

print(true)           //"true\n"
print(p1)             //"true\n"

Int(true)             //1

print(NSNumber(value: p1))   

Answer 3

Swift 4

Bool -> Int

extension Bool {
    var intValue: Int {
        return self ? 1 : 0
    }
}

Int -> Bool

extension Int {
    var boolValue: Bool {
        return self != 0 
    }
}

Answer 4

Try this,

let p1 = ("a" == "a") //true
print(true)           //"true\n"
print(p1)             //"true\n"

Int(true)             //1

Int(NSNumber(value:p1)) //1

Answer 5

You could use the ternary operator to convert a Bool to Int:

let result = condition ? 1 : 0

result will be 1 if condition is true, 0 is condition is false.

Answer 6

You could use hashValue property:

let active = true
active.hashValue // returns 1
active = false
active.hashValue // returns 0