SplDoublyLinkedList::setIteratorMode

    (PHP 5 >= 5.3.0, PHP 7, PHP 8)

    SplDoublyLinkedList::setIteratorMode — Устанавливает режим итерации

    Описание

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

    Список параметров

    mode

    Существуют два ортогональных набора режимов, которые могут быть установлены:

    По умолчанию используется режим: SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_KEEP

    Внимание

    Направление итерации нельзя изменить для классов SplStack и SplQueue, оно всегда SplDoublyLinkedList::IT_MODE_FIFO. Попытка изменить его приведёт к выбрасыванию исключения RuntimeException.

    Возвращаемые значения

    Возвращает различные режимы и флаги, влияющие на итерацию.

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    Инструкция • Исправление • Сообщение об ошибке
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    Примечания пользователей 2 notes

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    3
    gregorypatmore at gmail dot com
    12 years ago
    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.
    up
    2
    pritiatwork at gmail dot com
    13 years ago
    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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