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<?php class DataContainer implements IteratorAggregate { protected $data; public function __construct(array $data) { $this->data = $data; } public function &getIterator() { foreach ($this->data as $key => &$value) { yield $key => $value; } } } $dataContainer = new DataContainer([1, 2, 3]); foreach (array_keys((array)$dataContainer) as $key) { $dataContainer[$key] *= -1; } var_dump($dataContainer);

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39.85 ms | 402 KiB | 5 Q