PHP standard library SPL data structure-----spldoublylinkedlist (doubly linked list)

          $SPL =new spldoublylinkedlist ();          Instantiate an object $spl->push ("Sdfsaf") of a doubly linked list;  Added to the top (top) (tail) of the list $SPL->push (111);  $SPL->push (' 1 ');        $SPL->unshift ("100"); The value added to the bottom of the list (bottom) (head) value in the doubly linked list $SPL->shift (); //Delete bottom (head) at the location of the values         &NB SP; $spl->pop ();  //pop-up top value   $SPL->top ();    //get Top (trailing) elements $SPL-&G  T;count () Number of; //nodes          $SPL->isempty (); is currently empty, returns true for null     $SPL->rewind ();    //move to bottom (head) position    &NB sp;      $spl->current (); //Get the value of the current node $spl->next ();  //Move the node down  &N                         bsp;         $spl->prev ();  //Return to previous node//Loop through linked list   $SPL->rewind ();              &NBsp  while ($name = $spl->current ()) {                       echo $name. " \ n ";                      $SPL Next ();                 }/******************* /          &nbs P     for ($spl->rewind (); $spl->valid (); $spl->next ()) {                        echo $spl->current (). " \ n ";            } var_dump ($spl->valid ()); Returns true if the node is a valid node, otherwise false//NOTE: When $spl->current (), $SPL->valid () must be $spl->rewind (); Otherwise point to empty nodes  

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