The SplDoublyLinkedList class

(PHP 5 >= 5.3.0)

Einführung

The SplDoublyLinkedList class provides the main functionalities of a doubly linked list.

Klassenbeschreibung

SplDoublyLinkedList implements Iterator , ArrayAccess , Countable {
/* Methoden */
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 )
}

Inhaltsverzeichnis

add a note add a note

User Contributed Notes 2 notes

up
11
Gilles A
1 year ago
FIFO and LIFO in SplDoublyLinkedList

$list = new SplDoublyLinkedList();
$list->push('a');
$list->push('b');
$list->push('c');
$list->push('d');

echo "FIFO (First In First Out) :\n";
$list->setIteratorMode(SplDoublyLinkedList::IT_MODE_FIFO);
for ($list->rewind(); $list->valid(); $list->next()) {
    echo $list->current()."\n";
}

Result :

// FIFO (First In First Out):
// a
// b
// c
// d

echo "LIFO (Last In First Out) :\n";
$list->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO);
for ($list->rewind(); $list->valid(); $list->next()) {
    echo $list->current()."\n";
}

Result :

// LIFO (Last In First Out):
// d
// c
// b
// a
up
1
Maaz Rehman
7 days ago
/*
php doubly link list is an amazing data structure ,doubly means you can traverse forward as well as backward, it can act as a deque(double ended queue) if you want it to,
here is how it works

*/

//instantiating an object of doubly link list

$dlist=new SplDoublyLinkedList();

//a push inserts data at the end of the list
$dlist->push('hiramariam');
$dlist->push('maaz');
$dlist->push('zafar');

/* the list contains
hiramariam
maaz
zafar
*/

//while an unshift inserts an object at top of the list
$dlist->unshift(1);
$dlist->unshift(2);
$dlist->unshift(3);

/* the list now contains
3
2
1
hiramariam
maaz
zafar
*/

//you can delete an item from the bottom of the list by using pop
$dlist->pop();

/* the list now contains
3
2
1
hiramariam
maaz

*/
//you can delete an item from the top of the list by using shift()
$dlist->shift();

/* the list now contains

2
1
hiramariam
maaz

*/

/* if you want to replace an item at particular index you can use a method named add , note that if you want to replace an item that does not exist , an exception will be thrown*/

$dlist->add(3 , 2.24);

/*
to go through the list we use a simple for loop, the rewind() method shown below point to the initials of the list depending on the iterator, a valid() method checks whether a list is still valid or not , meaning it ensures the loop does not go on and on after we reach the last data in the list , and the next() method simply points to the next data in the list.

*/
for($dlist->rewind();$dlist->valid();$dlist->next()){
   
    echo $dlist->current()."<br/>";
    }
echo "<br/>";
/*

To traverse backward

*/
$dlist->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO);
for($dlist->rewind();$dlist->valid();$dlist->next()){
   
    echo $dlist->current()."<br/>";;
    }
To Top