Get integer value from string in swift

Question

So I can do this:

var stringNumb: NSString = \"1357\"

var someNumb: CInt = stringNumb.intValue

But I can\'t find the way to do it w/ a

Answer 1

Swift 2.0 you can initialize Integer using constructor

var stringNumber = "1234"
var numberFromString = Int(stringNumber)

Answer 2

In Swift 3.0

Type 1: Convert NSString to String

    let stringNumb:NSString = "1357"
    let someNumb = Int(stringNumb as String) // 1357 as integer

Type 2: If the String has Integer only

    let stringNumb = "1357"
    let someNumb = Int(stringNumb) // 1357 as integer

Type 3: If the String has Float value

    let stringNumb = "13.57"
    if let stringToFloat = Float(stringNumb){
        let someNumb = Int(stringToFloat)// 13 as Integer
    }else{
       //do something if the stringNumb not have digit only. (i.e.,) let stringNumb = "13er4"
    }

Answer 3

Simple but dirty way

// Swift 1.2
if let intValue = "42".toInt() {
    let number1 = NSNumber(integer:intValue)
}
// Swift 2.0
let number2 = Int(stringNumber)

// Using NSNumber
let number3 = NSNumber(float:("42.42" as NSString).floatValue)

The extension-way

This is better, really, because it'll play nicely with locales and decimals.

extension String {

    var numberValue:NSNumber? {
        let formatter = NSNumberFormatter()
        formatter.numberStyle = .DecimalStyle
        return formatter.numberFromString(self)
    }
}

Now you can simply do:

let someFloat = "42.42".numberValue
let someInt = "42".numberValue

Answer 4

If you are able to use a NSString only.

It's pretty similar to objective-c. All the data type are there but require the as NSString addition

    var x = "400.0" as NSString 

    x.floatValue //string to float
    x.doubleValue // to double
    x.boolValue // to bool
    x.integerValue // to integer
    x.intValue // to int

Also we have an toInt() function added See Apple Inc. “The Swift Programming Language.” iBooks. https://itun.es/us/jEUH0.l page 49

x.toInt()

Answer 5

A more general solution could be a extension

extension String {
    var toFloat:Float {
        return Float(self.bridgeToObjectiveC().floatValue)
    }
    var toDouble:Double {
        ....
    }
    ....
}

this for example extends the swift native String object by toFloat

Answer 6

8:1 Odds(*)

var stringNumb: String = "1357"
var someNumb = Int(stringNumb)

or

var stringNumb: String = "1357"
var someNumb:Int? = Int(stringNumb)

Int(String) returns an optional Int?, not an Int.

---

Safe use: do not explicitly unwrap

let unwrapped:Int = Int(stringNumb) ?? 0

or

if let stringNumb:Int = stringNumb { ... }

(*) None of the answers actually addressed why var someNumb: Int = Int(stringNumb) was not working.