由于需要对一组数据多次进行移动操作，所以写个双向链表。但对php实在不熟悉，虽然测试各个方法没啥问题，就是不知道php语言深层的这些指针和unset有什么注意的地方，贴出来让大家教育吧。效率没测试....求谅解～
<?php /** * **双向链表 * @author zhiyuan12@ */ /** * 链表元素结点类 */ class node_element { public $pre = null; // 前驱 public $next = null; // 后继 public $key = null; // 元素键值 public $data = null; // 结点值 function construct($key, $data) { $this->key = $key; $this->data = $data; } } /** * 双向链表类 */ class doublelinkedlist { private $head; // 头指针 private $tail; // 尾指针 private $current; // 当前指针 private $len; // 链表长度 function construct() { $this->head = self::_getnode ( null, null ); $this->curelement = $this->head; $this->tail = $this->head; $len = 0; } /** * @ desc: 读取链表全部结点 */ public function readall() { $tmp = $this->head; while ( $tmp->next !== null ) { $tmp = $tmp->next; var_dump ( $tmp->key, $tmp->data ); } } public function move($pos1, $pos2) { $pos1node = $this->findposition ( $pos1 ); $pos2node = $this->findposition ( $pos2 ); if ($pos1node !== null && $pos2node !== null) { $tmpkey = $pos1node->key; $tmpdata = $pos1node->data; $pos1node->key = $pos2node->key; $pos1node->data = $pos2node->data; $pos2node->key = $tmpkey; $pos2node->data = $tmpdata; return true; } return false; } /** * @ desc: 在指定关键词删除结点 * * @param : $key * 指定位置的链表元素key */ public function delete($key) { $pos = $this->find ( $key ); if ($pos !== null) { $tmp = $pos; $last = null; $first = true; while ( $tmp->next !== null && $tmp->next->key === $key ) { $tmp = $tmp->next; if (! $first) { $this->delnode ( $last ); } else { $first = false; } $last = $tmp; } if ($tmp->next !== null) { $pos->pre->next = $tmp->next; $tmp->next->pre = $pos->pre; } else { $pos->pre->next = null; } $this->delnode ( $pos ); $this->delnode ( $tmp ); } } /** * @ desc: 在指定位置删除结点 * * @param : $key * 指定位置的链表元素key */ public function deleteposition($pos) { $tmp = $this->findposition ( $pos ); if ($tmp === null) { return true; } if ($tmp === $this->gettail ()) { $tmp->pre->next = null; $this->delnode ( $tmp ); return true; } $tmp->pre->next = $tmp->next; $tmp->next->pre = $tmp->pre; $this->delnode ( $tmp ); } /** * @ desc: 在指定键值之前插入结点 * * @param : $key * //指定位置的链表元素key * @param : $data * //要插入的链表元素数据 * @param : $flag * //是否顺序查找位置进行插入 */ public function insert($key, $data, $flag = true) { $newnode = self::_getnode ( $key, $data ); $tmp = $this->find ( $key, $flag ); if ($tmp !== null) { $newnode->pre = $tmp->pre; $newnode->next = $tmp; $tmp->pre = $newnode; $newnode->pre->next = $newnode; } else { $newnode->pre = $this->tail; $this->tail->next = $newnode; $this->tail = $newnode; } $this->len ++; } /** * @ desc: 在指定位置之前插入结点 * * @param : $pos * 指定插入链表的位置 * @param : $key * 指定位置的链表元素key * @param : $data * 要插入的链表元素数据 */ public function insertposition($pos, $key, $data) { $newnode = self::_getnode ( $key, $data ); $tmp = $this->findposition ( $pos ); if ($tmp !== null) { $newnode->pre = $tmp->pre; $newnode->next = $tmp; $tmp->pre = $newnode; $newnode->pre->next = $newnode; } else { $newnode->pre = $this->tail; $this->tail->next = $newnode; $this->tail = $newnode; } $this->len ++; return true; } /** * @ desc: 根据key值查询指定位置数据 * * @param : $key * //指定位置的链表元素key * @param : $flag * //是否顺序查找 */ public function find($key, $flag = true) { if ($flag) { $tmp = $this->head; while ( $tmp->next !== null ) { $tmp = $tmp->next; if ($tmp->key === $key) { return $tmp; } } } else { $tmp = $this->gettail (); while ( $tmp->pre !== null ) { if ($tmp->key === $key) { return $tmp; } $tmp = $tmp->pre; } } return null; } /** * @ desc: 根据位置查询指定位置数据 * * @param : $pos * //指定位置的链表元素key */ public function findposition($pos) { if ($pos <= 0 || $pos > $this->len) return null; if ($pos < ($this->len / 2 + 1)) { $tmp = $this->head; $count = 0; while ( $tmp->next !== null ) { $tmp = $tmp->next; $count ++; if ($count === $pos) { return $tmp; } } } else { $tmp = $this->tail; $pos = $this->len - $pos + 1; $count = 1; while ( $tmp->pre !== null ) { if ($count === $pos) { return $tmp; } $tmp = $tmp->pre; $count ++; } } return null; } /** * @ desc: 返回链表头节点 */ public function gethead() { return $this->head->next; } /** * @ desc: 返回链表尾节点 */ public function gettail() { return $this->tail; } /** * @ desc: 查询链表节点个数 */ public function getlength() { return $this->len; } private static function _getnode($key, $data) { $newnode = new node_element ( $key, $data ); if ($newnode === null) { echo new node fail!; } return $newnode; } private function delnode($node) { unset ( $node ); $this->len --; } } $mylist = new doublelinkedlist (); $mylist->insert ( 1, test1 ); $mylist->insert ( 2, test2 ); $mylist->insert ( 2b, test2-b ); $mylist->insert ( 2, test2-c ); $mylist->insert ( 3, test3 ); $mylist->insertposition ( 5, t, testt ); $mylist->readall (); echo +++; $mylist->deleteposition(0); $mylist->readall (); echo ... . $mylist->getlength (); var_dump ( $mylist->findposition ( 3 )->data ); ?>
运行结果：
int(1) string(5) test1 int(2) string(7) test2-c int(2) string(5) test2 string(2) 2b string(7) test2-b string(1) t string(5) testt int(3) string(5) test3 +++int(1) string(5) test1 int(2) string(7) test2-c int(2) string(5) test2 string(2) 2b string(7) test2-b string(1) t string(5) testt int(3) string(5) test3 ...6string(5) test2
相信看了本文案例你已经掌握了方法，更多精彩请关注其它相关文章！
推荐阅读：
php删除数组中指定下标元素步骤详解
php实现对图片的反色处理步骤详解
以上就是php双向链表使用详解的详细内容。