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

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.