Optionals

optionals.swift

// variables declaration
var str = "Hello, playground"
var x = Int(10)

// class definition
class ParentClass {
    func writeText(_ text: String?) -> Void {
        print("\(text ?? "empty text")")
    }
}

var p: ParentClass? = ParentClass()
p?.writeText("Hello there!")



// Optionals
var myString:String?

// Check if myString is not nil
if myString != nil {
    print(myString!)
} else {
    print("myString has nil value")
}

// Assign myString with a value
myString = "I'm a text 😁"

// Check it again
if myString != nil {
    print(myString!)
}

// This is the recommended way to check if variable has a value
if let count = myString?.count {
    print(count)
}
// But a bit cumbersome to write this again and again
// I want something like this:
// #if myString?.count {
// # ...
// #}