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SplDoublyLinkedList::setIteratorMode

(PHP 5 >= 5.3.0, PHP 7)

SplDoublyLinkedList::setIteratorMode — Sets the mode of iteration

说明

public SplDoublyLinkedList::setIteratorMode ( int $mode ) : void

参数

mode

There are two orthogonal sets of modes that can be set:

The direction of the iteration (either one or the other):
- SplDoublyLinkedList::IT_MODE_LIFO (Stack style)
- SplDoublyLinkedList::IT_MODE_FIFO (Queue style)
The behavior of the iterator (either one or the other):
- SplDoublyLinkedList::IT_MODE_DELETE (Elements are deleted by the iterator)
- SplDoublyLinkedList::IT_MODE_KEEP (Elements are traversed by the iterator)

The default mode is: SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_KEEP

返回值

没有返回值。

User Contributed Notes

gregorypatmore at gmail dot com 11-Dec-2011 11:15


Despite the seeming unrelated-ness between the FIFO/LIFO and the KEEP/DELETE option pairs, in respect to the behavior of setIteratorMode they are in some way linked.  Meaning, a second call to setIteratorMode will erase any previous settings even if they are from the other pair.  This, coupled with the default settings for the object (SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_KEEP), means you have to be careful or you can run into trouble





Consider the following example:





<?php


$l = new SPLDoublyLinkedList();


$l->setIteratorMode(SplDoublyLinkedList::IT_MODE_DELETE);


$l->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO);





$mode = $l->getIteratorMode();


var_dump("MODE: $mode");


var_dump("MODE CHECKS");


var_dump(($mode & SplDoublyLinkedList::IT_MODE_LIFO) == SplDoublyLinkedList::IT_MODE_LIFO);


var_dump(($mode & SplDoublyLinkedList::IT_MODE_FIFO) == SplDoublyLinkedList::IT_MODE_FIFO);


var_dump(($mode & SplDoublyLinkedList::IT_MODE_DELETE) == SplDoublyLinkedList::IT_MODE_DELETE);


var_dump(($mode & SplDoublyLinkedList::IT_MODE_KEEP) == SplDoublyLinkedList::IT_MODE_KEEP);





$l->push('A');


$l->push('B');


$l->push('C');


$l->push('D');


$l->rewind();





var_dump("Traversing");


var_dump($l->isEmpty());





var_dump($l->count());


var_dump($l->current());


$l->next();





var_dump($l->count());


var_dump($l->current());


$l->next();





var_dump($l->count());


var_dump($l->current());


$l->next();





var_dump($l->count());


var_dump($l->current());


$l->next();





var_dump($l->count());


var_dump($l->isEmpty());





?>





Which outputs the following:


#############################


string(7) "MODE: 2"





string(11) "MODE CHECKS"


bool(true) #LIFO (ok)


bool(true) #FIFO (umm...wait a minute)


bool(false)#DELETE (houston... wtf)


bool(true) #KEEP (ok, where's the camera hidden)





string(10) "Traversing"


bool(false)





int(4)


string(1) "D"





int(4)


string(1) "C"





int(4)


string(1) "B"





int(4)


string(1) "A"





int(4)


bool(false)


#############################





Basically, you should just check the non-zero flags (LIFO(2) and DELETE(1)).  Since it's an either/or situation within the pairs, this should be able to help you figure out the separate mode pieces an instance has been set to.





example:





<?php


$l = new SPLDoublyLinkedList();


$l->setIteratorMode(SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_DELETE);





$mode = $l->getIteratorMode();





$isLIFO = ($mode & SplDoublyLinkedList::IT_MODE_LIFO) == SplDoublyLinkedList::IT_MODE_LIFO;





$isDELETE = ($mode & SplDoublyLinkedList::IT_MODE_DELETE) == SplDoublyLinkedList::IT_MODE_DELETE;


?>





hope this helps someone.

pritiatwork at gmail dot com 07-Sep-2011 11:39


Usage of different Iterator Mode



<?php

$doubly=new SplDoublyLinkedList();

$doubly->push(array('name'=>'Naruto'));

$doubly->push(array('name'=>'Sakura'));

$doubly->push(array('name'=>'Neji'));

$doubly->push(array('name'=>'Sasuke'));

var_dump($doubly);

echo '<br/> FIFO Traversing<br/>';

$doubly->setIteratorMode(SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_KEEP);

$doubly->rewind();

foreach($doubly as $key=>$value)

{

    echo '<br/>Traversed:'.$key.' '.$value['name'];

}

echo '<br/>LIFO Traversing - Keep mode <br/>';

$doubly->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO | SplDoublyLinkedList::IT_MODE_KEEP);

$doubly->rewind();

foreach($doubly as $key=>$value)

{

    echo '<br/>Traversed:'.$key.' '.$value['name'];

}



echo '<br/>LIFO Traversing - Delete mode <br/>';

$doubly->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO | SplDoublyLinkedList::IT_MODE_DELETE);

$doubly->rewind();



foreach($doubly as $key=>$value)

{

    if($key == 2) break;

    echo '<br/>Traversed:'.$key.' '.$value['name'];

}

var_dump($doubly);

?>



Output:



FIFO Traversing



Traversed:0 Naruto

Traversed:1 Sakura

Traversed:2 Neji

Traversed:3 Sasuke

LIFO Traversing - Keep mode 



Traversed:3 Sasuke

Traversed:2 Neji

Traversed:1 Sakura

Traversed:0 Naruto

LIFO Traversing - Delete mode 



Traversed:3 Sasuke

object(SplDoublyLinkedList)#1 (2) {

  ["flags":"SplDoublyLinkedList":private]=>

  int(3)

  ["dllist":"SplDoublyLinkedList":private]=>

  array(3) {

    [0]=>

    array(1) {

      ["name"]=>

      string(6) "Naruto"

    }

    [1]=>

    array(1) {

      ["name"]=>

      string(6) "Sakura"

    }

    [2]=>

    array(1) {

      ["name"]=>

      string(4) "Neji"

    }

  }

}

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SplDoublyLinkedList::setIteratorMode

说明

参数

返回值

User Contributed Notes

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