Strings in Switch Statements: 'String' does not conform to protocol 'IntervalType'

Question

I am having problems using strings in switch statements in Swift.

I have a dictionary called opts which is declared as

Answer 1

I had this same error message inside prepareForSegue(), which I imagine is fairly common. The error message is somewhat opaque but the answers here got me on the right track. If anyone encounters this, you don't need any typecasting, just a conditional unwrap around the switch statement:-

if let segueID = segue.identifier {
    switch segueID {
        case "MySegueIdentifier":
            // prepare for this segue
        default:
            break
    }
}