Arrays have built-in methods for removing the first or last items, but there’s a subtle difference between them.
First, there are two ways of removing the last item:
removeLast(). Both remove the last item from the array, but
popLast() returns an optional – if the array was empty, you get back nil. If you call
removeLast() on an empty array, your app crashes.
So, in this example
last1 will contain 5 and
last2 will contain 4:
var numbers = [1, 2, 3, 4, 5] let last1 = numbers.popLast() let last2 = numbers.removeLast()
As for removing items from the start of the array, there’s only one method:
removeFirst(). This, like
removeLast(), will crash your app if called when the array is empty.
So, continuing the above example, this will put 1 into
let first1 = numbers.removeFirst()
There is no
popFirst() because it’s an expensive operation and the developers want you to think twice – each time you remove an item from the front the rest of the items have to move down, so trying to use
popFirst() in a loop would be inefficient.
Available from iOS 8.0
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Upgrade to premium
The Hacking with Swift guide book helps you learn faster, plus get an Xcode tips and tricks video and Swift wall chart.