SplDoublyLinkedList::IT_MODE_LIFO: The list will be iterated in a last in, first out order, like a stack.
SplDoublyLinkedList::IT_MODE_FIFO: The list will be iterated in a first in, first out order, like a queue.

Iteration Behavior

SplDoublyLinkedList::IT_MODE_DELETE: Iteration will remove the iterated elements.
SplDoublyLinkedList::IT_MODE_KEEP: Iteration will not remove the iterated elements.

SplDoublyLinkedList::add — Add/insert a new value at the specified index
SplDoublyLinkedList::bottom — Peeks at the node from the beginning of the doubly linked list
SplDoublyLinkedList::count — Counts the number of elements in the doubly linked list
SplDoublyLinkedList::current — Return current array entry
SplDoublyLinkedList::getIteratorMode — Returns the mode of iteration
SplDoublyLinkedList::isEmpty — Checks whether the doubly linked list is empty
SplDoublyLinkedList::key — Return current node index
SplDoublyLinkedList::next — Move to next entry
SplDoublyLinkedList::offsetExists — Returns whether the requested $index exists
SplDoublyLinkedList::offsetGet — Returns the value at the specified $index
SplDoublyLinkedList::offsetSet — Sets the value at the specified $index to $value
SplDoublyLinkedList::offsetUnset — Unsets the value at the specified $index
SplDoublyLinkedList::pop — Pops a node from the end of the doubly linked list
SplDoublyLinkedList::prev — Move to previous entry
SplDoublyLinkedList::push — Pushes an element at the end of the doubly linked list
SplDoublyLinkedList::rewind — Rewind iterator back to the start
SplDoublyLinkedList::serialize — Serializes the storage
SplDoublyLinkedList::setIteratorMode — Sets the mode of iteration
SplDoublyLinkedList::shift — Shifts a node from the beginning of the doubly linked list
SplDoublyLinkedList::top — Peeks at the node from the end of the doubly linked list
SplDoublyLinkedList::unserialize — Unserializes the storage
SplDoublyLinkedList::unshift — Prepends the doubly linked list with an element
SplDoublyLinkedList::valid — Check whether the doubly linked list contains more nodes

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User Contributed Notes 6 notes

down

Gilles A ¶

11 years 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

down

Maaz Rehman ¶

9 years 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/>";;
    }

down

dongchao769390531 at 163 dot com ¶

7 years ago

<?php
$splDoubleLinkedList = new SplDoublyLinkedList();
$splDoubleLinkedList->push('a');
$splDoubleLinkedList->push('3');
$splDoubleLinkedList->push('v');
$splDoubleLinkedList->push('1');
$splDoubleLinkedList->push('p');
//First of all, we need rewind list
$splDoubleLinkedList->rewind();
//Use while, check if the list has valid node
while ($splDoubleLinkedList->valid()){
    //Print current node's value
    echo $splDoubleLinkedList->current()."\n";
    //Turn the cursor to next node
    $splDoubleLinkedList->next();
}
?>

down

77931774 at qq dot com ¶

3 years ago

$list = new SplDoublyLinkedList();

for ($i = 0; $i < 2000001; $i++) {
    $list->push($i);
}

$s = microtime(true);

//$res = $list->offsetGet(2000000);     // spend 7 ms
$res = $list->offsetGet(0);               // spend 0.07 ms
var_dump($res);

$e = microtime(true);

echo ($e - $s) * 1000;

down

Premysl Karbula ¶

1 year ago

A function which replaces some portion od doubly linked list (DLL) with items from specified array.

<?php

/**
 * Replace some portion (specified by index and length) of DLL with items
 * from the specified replacement array.
 */
public function dll_splice(
    \SplDoublyLinkedList $dll,
    int $start,
    int $length,
    array $replacement,
): void {

    if ($start < 0 || ($start + $length) > $dll->count()) {
        throw new \OutOfRangeException("Invalid range for splicing");
    }

    for ($i = 0; $i < $length; $i++) {
        $dll->offsetUnset($start);
    }

    foreach ($replacement as $item) {
        $dll->add($start, $item);
    }

}

?>

down

-2

lincoln dot du dot j at gmail dot com ¶

7 years ago

$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]);
}

$a->push(11); //push method
$a->add(10,12); //add method must with index
$a->shift(); //remove array first value
$a->unshift(1); //add first value

$a->rewind(); //initial from first 

echo "SplDoublyLinkedList array last/top value " .  $a->top() ." \n";
echo "SplDoublyLinkedList array count value " .  $a->count() ." \n";
echo "SplDoublyLinkedList array first/top value " . $a->bottom() . " \n\n";

while($a->valid()){ //check with valid method
    echo 'key ', $a->key(), ' value ', $a->current(),"\n"; //key and current method use here
    $a->next(); //next method use here
}

$a->pop(); //remove array last value
print_r($a);
$s=$a->serialize();
echo $s;

//Output
SplDoublyLinkedList array last/top value 12 
SplDoublyLinkedList array count value 11 
SplDoublyLinkedList array first/top value 1 

key 0 value 1
key 1 value 2
key 2 value 3
key 3 value 4
key 4 value 5
key 5 value 6
key 6 value 7
key 7 value 8
key 8 value 9
key 9 value 11
key 10 value 12
SplDoublyLinkedList Object
(
    [flags:SplDoublyLinkedList:private] => 0
    [dllist:SplDoublyLinkedList:private] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
            [4] => 5
            [5] => 6
            [6] => 7
            [7] => 8
            [8] => 9
            [9] => 11
        )

)
i:0;:i:1;:i:2;:i:3;:i:4;:i:5;:i:6;:i:7;:i:8;:i:9;:i:11;

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The SplDoublyLinkedList class

Introduction

Class synopsis

Predefined Constants

Iteration Direction

Iteration Behavior

Table of Contents

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User Contributed Notes 6 notes