Swift: Test class type in switch statement
You absolutely can use is
in a switch
block. See "Type Casting for Any and AnyObject" in the Swift Programming Language (though it's not limited to Any
of course). They have an extensive example:
for thing in things {
switch thing {
case 0 as Int:
println("zero as an Int")
case 0 as Double:
println("zero as a Double")
case let someInt as Int:
println("an integer value of \(someInt)")
case let someDouble as Double where someDouble > 0:
println("a positive double value of \(someDouble)")
// here it comes:
case is Double:
println("some other double value that I don't want to print")
case let someString as String:
println("a string value of \"\(someString)\"")
case let (x, y) as (Double, Double):
println("an (x, y) point at \(x), \(y)")
case let movie as Movie:
println("a movie called '\(movie.name)', dir. \(movie.director)")
default:
println("something else")
}
}
Putting up the example for "case is - case is Int, is String:" operation, where multiple cases can be used clubbed together to perform the same activity for Similar Object types. Here "," separating the types in case is operating like a OR operator.
switch value{
case is Int, is String:
if value is Int{
print("Integer::\(value)")
}else{
print("String::\(value)")
}
default:
print("\(value)")
}
Demo Link
In case you don't have a value, just any object:
swift 4
func test(_ val:Any) {
switch val {
case is NSString:
print("it is NSString")
case is String:
print("it is a String")
case is Int:
print("it is int")
default:
print(val)
}
}
let str: NSString = "some nsstring value"
let i:Int=1
test(str)
// it is NSString
test(i)
// it is int