How do you unwrap Swift optionals?

Question

How do you properly unwrap both normal and implicit optionals?

There seems to be confusion in this topic and I would just like to have a reference for all of the way

Answer 1

Since Beta 5 we have also the new coalescing operator (??):

var a : Int?
let b : Int = a ?? 0

If the optional is != nil it is unwrapped else the value on the right of the operator is used