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<?php function b(&$v) { $v = 0; } $ar = [[1, 2, 3, 4], [1, 2, 3, 4]]; foreach ($ar as &$v) { foreach ($v as $v1) { b($v1); } } unset($v); var_dump($ar);

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35.9 ms | 402 KiB | 5 Q