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NoRewindIterator::__construct »

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NoRewindIterator クラス

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

はじめに

このイテレータは巻き戻しの操作を無視します。これにより、一部のみを走査する複数の foreach ループでイテレータを処理することが可能になります。

クラス概要

class NoRewindIterator extends IteratorIterator {

/* メソッド */

public __construct(Iterator $iterator)

public current(): mixed

public key(): mixed

public next(): void

public rewind(): void

public valid(): bool

/* 継承したメソッド */

public IteratorIterator::current(): mixed

public IteratorIterator::getInnerIterator(): ?Iterator

public IteratorIterator::key(): mixed

public IteratorIterator::next(): void

public IteratorIterator::rewind(): void

public IteratorIterator::valid(): bool

}

目次

NoRewindIterator::__construct — NoRewindIterator を作成する
NoRewindIterator::current — 現在の値を取得する
NoRewindIterator::key — 現在のキーを取得する
NoRewindIterator::next — 次の要素に移動する
NoRewindIterator::rewind — 内部イテレータの巻き戻し操作を阻止する
NoRewindIterator::valid — イテレータの有効性を検証する

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User Contributed Notes 1 note

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7

Anonymous ¶

4 years ago

As its name implies, NoRewindIterator doesn't invoke the "rewind" method when It reaches the end of the iterator.

Let's demonstrate it by two examles.

In this example the "rewind" method will be invoked after when the "foreache" reaches its end, so, we can repeat printing the same values as many times as we want:

<?PHP
$iterator = new ArrayIterator(['PHP', 'Python', 'Go']);

foreach ($iterator as $item) {
    echo $item.PHP_EOL;
}

foreach ($iterator as $item) {
    echo $item.PHP_EOL;
}
?>

By using the NoRewindIterator, the "rewind" won't be invoked, so, we can't do as we did in previous example:

<?PHP
$iterator = new ArrayIterator(['PHP', 'Python', 'Go']);
$iterator = new NoRewindIterator($iterator);

foreach ($iterator as $item) {
    echo $item.PHP_EOL;
}

// doesn't do anything
foreach ($iterator as $item) {
    echo $item.PHP_EOL;
}

?>