using let

As it says in the Apple docs:

mutating func removeLast() -> T

You can see that the function returns the element that has been removed (T is a generic, as an array can contain elements of any type). So as Josue Gisber pointed out, you can assign the result of removeLast() to a variable/constant.

You don't have to, however, so this is all valid code:

var array = ["one", "two", "three"]

// Removes "three"
array.removeLast()

// Removes "two", assigns it to `lastRemovedElement` and logs it
let lastRemovedElement = array.removeLast()
print("Removed \(lastRemovedElement) from array")

When you add the let item = to the front of todo.removeLast(), you are assigning the last item in the todo array to the constant item; whereas if you just did todo.removeLast(), you would just remove the last item from the todo array

Thank you all. I get it know. As Martin Wildfeuer pointed in his example, I still can use that var if i assign it as a constant.

I´m from Angola, and portuguese is my native language. So it´s not easy to me to assimilate, that is way i wacth the videos at least 2 times.

Thanks.