Casting a variable of generic data type to String in Swift

Question

I have a generic class which contains a variable of generic data type. I need to convert this variable to String.

Example Code -

class test<T> {
var value:T!
var name: String!

  init(text: String, val: T)
  {
    name = text
    value = val
  }

  func toString() -> String {
    let temp = value as! String
    //let temp = String(value)
    return name + ": " + temp 
  }
}

I tried down-casting it by doing let temp = value as! String but it leads to crash during run time

Doing let temp = String(value) throws Cannot invoke initializer for type 'String' with an argument list of type '(T?)' build error

the crash won't happen if you specify T as String , can you show creation of test ? — Shehata Gamal
– Shehata Gamal, Commented Jan 16, 2019 at 21:45

David Pasztor · Accepted Answer · 2019-01-16 21:47:44Z

3

You can use String interpolation to include value in a String.

class Test<T> {
    var value:T
    var name: String

    init(text: String, val: T) {
        name = text
        value = val
    }

    func toString() -> String {
        return "\(name): \(value)"
    }
}

Unrelated to your issue, but don't declare any of your variables as implicitly unwrapped Optionals (! after their type), especially not when you are setting them in the initializer. You should also conform to the Swift naming convention, which is UpperCamelCase for types (Test).

answered Jan 16, 2019 at 21:47

David Pasztor

55.1k9 gold badges97 silver badges130 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Casting a variable of generic data type to String in Swift

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related