extension Array where Element: StringLiteralConvertible{
func spliteByPrefix() -> [Element]{
for item in self{
}
return []
}
}
I want to write an extension of Array whose Element is always a String. And in my spliteByPrefix() function, i want to use maybe item.characters or something else which a String has. How?
As for now, you cannot write an extension of Array "whose Element is always a String" in Swift.
But you can write some extension which has nearly the same functionality.
Write your own protocol, which String can conform to:
protocol MyStringType {
var characters: String.CharacterView { get }
//You may need some other properties or methods to write your extension...
}
// Make `String` the only type conforming to `MyStringType`.
extension String: MyStringType {}
And write an extension where Element conforms to the protocol.
extension Array where Element: MyStringType {
func spliteByPrefix() -> [Element]{ //You really want to return, `Array<Element>`?
for item in self {
for ch in item.characters {
//Do something with `ch`.
_ = ch
}
}
return []
}
}
In this example Element is always a Int. I use the elements themselves of the array
extension Array where Element: IntegerType {
func toString() -> [String] {
var result = [String]()
for value in self {
result.append(String(value))
}
return result;
}
}
Example of use:
let numberInt = [23, 10, 79, 3]
let numberString = numberInt.toString()
