Convert String to CGFloat in Swift

Question

I\'m new to Swift, how can I convert a String to CGFloat?

I tried:

var fl: CGFloat = str as CGFloat
var fl: CGFloat = (CGFloat)str
var fl: CGFloat = CGFl         


        

Answer 1

let myFloatNumber = CGFloat("4.22")

Answer 2

This is kind of a work around, but you can cast it as an NSString, then get the float value, then initialize a CGFloat from that value. Example:

let str = "1.02345332"
let foo = CGFloat((str as NSString).floatValue)

Answer 3

This works:

let str = "3.141592654"
let fl = CGFloat((str as NSString).floatValue)

Answer 4

You can make an extension that adds an init to CGFloat

extension CGFloat {

    init?(string: String) {

        guard let number = NumberFormatter().number(from: string) else {
            return nil
        }

        self.init(number.floatValue)
    }

}

Use it like so let x = CGFloat(xString)

Answer 5

in Swift 3.1

if let n = NumberFormatter().number(from: string) {
   let fl = CGFloat(n)
} 

or:

let fl = CGFloat((str as NSString).floatValue))

Answer 6

As of Swift 2.0, the Double type has a failable initializer that accepts a String. So the safest way to go from String to CGFloat is:

let string = "1.23456"
var cgFloat: CGFloat?

if let doubleValue = Double(string) {
    cgFloat = CGFloat(doubleValue)
}

// cgFloat will be nil if string cannot be converted

If you have to do this often, you can add an extension method to String:

extension String {

  func CGFloatValue() -> CGFloat? {
    guard let doubleValue = Double(self) else {
      return nil
    }

    return CGFloat(doubleValue)
  }
}

Note that you should return a CGFloat? since the operation can fail.