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    ArrayIterator::seek

    (PHP 5, PHP 7, PHP 8)

    ArrayIterator::seek — 位置を移動する

    説明

    public ArrayIterator::seek(int $offset): void

    イテレータ内の指定した位置に移動します。

    パラメータ

    offset

    移動する位置。

    戻り値

    値を返しません。

    エラー / 例外

    offset に移動できない場合は、 OutOfBoundsException をスローします。

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    User Contributed Notes 2 notes

    up
    6
    jon at ngsthings dot com
    16 years ago
    <?php
    // didn't see any code demos...here's one from an app I'm working on

    $array = array('1' => 'one',
    '2' => 'two',
    '3' => 'three');

    $arrayobject = new ArrayObject($array);
    $iterator = $arrayobject->getIterator();

    if(    $iterator->valid()){
    $iterator->seek(1); // expected: two, output: two
    echo $iterator->current(); // two
    }

    ?>
    up
    4
    foalford at gmail dot com
    8 years ago
    <?php
    //seek alter the iterator's internal indice instead of the value that key() returns.
    //This is a big trap if combining with uasort/natsort function.

    $a = new ArrayObject([4,3,2,1]);
    $it = $a->getIterator();
    $it->natsort(); //The Iterator preserve the key while sorting the array
    $it->rewind();
    $first = $it->key(); //The first element is 1 and it's key is 3
    echo $first. PHP_EOL; // 3

    $it->next();
    $second = $it->key();
    echo     $second. PHP_EOL; //2

    $it->next();
    $it->seek($first); //Was intended to seek to element 1, key 3, indice 0
    echo $it->key() . PHP_EOL; //end up 0 because seek took parameter as indice instead of key. It seek to element indice 3, element 4 key 0.

    var_dump($it);

    /* Output:
    3
    2
    0
    object(ArrayIterator)#2 (1) {
    ["storage":"ArrayIterator":private]=>
    object(ArrayObject)#1 (1) {
    ["storage":"ArrayObject":private]=>
    array(4) {
    [3]=>
    int(1)
    [2]=>
    int(2)
    [1]=>
    int(3)
    [0]=>
    int(4)
    }
    }
    }
    */
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