Cannot match values of type - swift

Question

I'm just starting out with Swift 3 and I'm converting a Rails project to swift (side project while I learn)
Fairly simple, I have a Rails statement Im converting and Im getting many red errors in Xcode:
let startingPoint: Int = 1
let firstRange: ClosedRange = (2...10)
let secondRange: ClosedRange = (11...20)
func calc(range: Float) -> Float {
switch range {
case startingPoint:
return (range - startingPoint) * 1 // or 0.2
case firstRange:
return // code
default:
return //code
}
}
calc will either have an Int or Float value: 10 or 10.50
Errors are:
Expression pattern of type ClosedRange cannot match values of type Float
Binary operator - cannot be applied to operands of type Float and Int
I understand the errors but I dont know what to search for to correct it. Could you point me in the right direction, please?

Answer 1

Swift is strongly typed. Whenever you use a variable or pass something as a function argument, Swift checks that it is of the correct type. You can't pass a string to a function that expects an integer etc. Swift does this check at compile time (since it's statically typed).
To adhere by that rules, try changing your code to this:
let startingPoint: Float = 1
let firstRange: ClosedRange<Float> = (2...10)
let secondRange: ClosedRange<Float> = (11...20)
func calc(range: Float) -> Float {
switch range {
case startingPoint:
return (range - startingPoint) * 1 // or 0.2
case firstRange:
return 1.0 // 1.0 is just an example, but you have to return Float since that is defined in the method
default:
return 0.0 // 0.0 is just an example, put whatever you need here
}
}

Answer 2

For the first error, you might want to specify ClosedRange to be of type Floats. Something similar to:
let firstRange: ClosedRange<Float> = (2...10)
For the second error, the problem is you are trying to compare a Float (range:Float) with an Int (startingPoint). So I would suggest you convert the startingPoint variable to a Float as well.