SplDoublyLinkedList::bottom()
(PHP 5 >= 5.3.0, PHP 7)
Peeks at the node from the beginning of the doubly linked list
说明
public SplDoublyLinkedList::bottom(void) : mixed
参数
此函数没有参数。
返回值
The value of the first node.
错误/异常
ThrowsRuntimeExceptionwhen the data-structure is empty.
A note on top() and bottom(): Picture the doubly-linked list (or queue) in the same way that you would a stack. Say you started with an empty queue, and added five values: $myList = new SplDoublyLinkedList $mylist->push(1) $mylist->push(2) $mylist->push(3) $mylist->push(4) $mylist->push(5) $mylist->top() -> 5 $mylist->bottom() -> 1
<?php /* * Examples of DoublyLinkedList */ $obj = new SplDoublyLinkedList(); // Check wither linked list is empty if ($obj->isEmpty()) { echo "Adding nodes to Linked List<br>"; $obj->push(2); $obj->push(3); echo "Adding the node at beginning of doubly linked list <br>"; $obj->unshift(10); } echo "<br>Our Linked List:"; print_r($obj); echo "<br>Pick the node from beginning of doubly linked list"; echo $obj->bottom(); ?>
$a = new SplDoublyLinkedList; $arr=[1,2,3,4,5,6,7,8,9]; for($i=0;$i<count($arr);$i++){ $a->add($i,$arr[$i]); } echo "SplDoublyLinkedList array last/top value " . $a->top() ." \n"; echo "SplDoublyLinkedList array first/top value " . $a->bottom() . " \n\n"; print_r($a); //Another Example $spl = new SplDoublyLinkedList; $spl->push(11); $spl->push(2); $spl->push(3); $spl->push(8); $spl->push(5); //array last value echo $spl->top(); echo PHP_EOL; //Array first value echo $spl->bottom(); echo PHP_EOL; print_r($spl);