In Swift \r\n is a single Character, just like \n

newline.swift

let str = "dupa\r\nblada"
for i in str.indices {
    switch str[i] {
        case "\n":
            print("\\n found") // \n not found
        case "\r":
            print("\\r found") // \r not found
        case "\r\n":
            print("\\r\\n found") // found
        default:
        break
    }
}

// if that'd be a simple tech interview question where you need to find \n, you guts are wrong and you failed

// To make life easier, treat string as collection of utf8 values
for i in Array(str.utf8).indices {
    switch Array(str.utf8)[i] {
        case "\n".utf8.first!:
            print("\\n found") // \n found
        case "\r".utf8.first!:
            print("\\r found") // \r found
        default:
        break
    }
}