In what situations is it recommended to use a linked list?

A linked list (LinkedList) is recommended to be used in situations where:

• Operations of inserting and deleting elements in the middle of the collection occur frequently, as LinkedList allows doing this efficiently without shifting elements, unlike arrays.
• Fast random access by index is not required, as LinkedList has linear time access.
• You need to implement a data structure with a dynamic size, where the number of elements often changes.

Example of usage in iOS (Swift):

class Node<T> {
    var value: T
    var next: Node?
    init(value: T) {
        self.value = value
    }
}

class LinkedList<T> {
    var head: Node<T>?
    
    func append(_ value: T) {
        let newNode = Node(value: value)
        if let lastNode = head {
            var current = lastNode
            while current.next != nil {
                current = current.next!
            }
            current.next = newNode
        } else {
            head = newNode
        }
    }
}

Thus, LinkedList is useful when the efficiency of insertions and deletions is important, rather than random access.