php標準庫(SPL)-資料結構(一)-SplDoublyLinkedList詳解____資料結構

SPL是用於解決典型問題(standard problems)的一組介面與類的集合。

1. SplDoublyLinkedList     
原型：

SplDoublyLinkedList implements Iterator , ArrayAccess , Countable {/* 方法 */public __construct ( void )public void add ( mixed $index , mixed $newval )public mixed bottom ( void )public int count ( void )public mixed current ( void )public int getIteratorMode ( void )public bool isEmpty ( void )public mixed key ( void )public void next ( void )public bool offsetExists ( mixed $index )public mixed offsetGet ( mixed $index )public void offsetSet ( mixed $index , mixed $newval )public void offsetUnset ( mixed $index )public mixed pop ( void )public void prev ( void )public void push ( mixed $value )public void rewind ( void )public string serialize ( void )public void setIteratorMode ( int $mode )public mixed shift ( void )public mixed top ( void )public void unserialize ( string $serialized )public void unshift ( mixed $value )public bool valid ( void )}

樣本：

 //Constructs a new doubly linked list    $list = new SplDoublyLinkedList();    //Pushes an element at the end of the doubly linked list    $list -> push('a');    $list -> push('b');    $list -> push('c');    $list -> push('d');    $list -> push('e');    $list -> push('f');    // Counts the number of elements in the doubly linked list.    $list -> count();    // Sets the mode of iteration    $list -> setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO);    // Returns the mode of iteration    $model = $list -> getIteratorMode();    /*  IT_MODE_LIFO => int(2)     *  IT_MODE_FIFO => int(0)     *  IT_MODE_DELETE => int(1)     *  IT_MODE_KEEP => int(0)      */    // Checks whether the doubly linked list is empty.    $list -> isEmpty();    // Return current node index    $list->key();    // Move to next entry    $list -> next();    // Returns whether the requested $index exists    $list -> offsetExists(3);      // Returns the value at the specified $index    $list -> offsetGet(3);    // Sets the value at the specified $index to $newval    $list -> offsetSet(3,'s');    // Unsets the value at the specified $index    $list -> offsetUnset(3);    // Pops a node from the end of the doubly linked list    $list -> pop();    // Peeks at the node from the end of the doubly linked list    $list -> top();    // Move to previous entry    $list -> prev();    // Rewind iterator back to the start    $list -> rewind();    // Serializes the storage    // $list -> serialize();    // Shifts a node from the beginning of the doubly linked list    $list -> shift();    // Prepends the doubly linked list with an element    $list -> unshift('s');    // Check whether the doubly linked list contains more nodes    $list -> valid();    for($list -> rewind();$list -> valid();$list -> next()){        //Return current array entry        echo $list -> current();    }