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<?php class Test { public $testdata = []; public function __construct(&$inputdata) { $this->testdata =& $inputdata; } public function &getIterator() { foreach ($this->testdata as $ikey => &$ivalue) { yield $ikey => $ivalue; } } } $data = array("one" => "Curly", "two" => "Larry", "three" => "Moe"); $t = new Test($data); foreach ($t->getIterator() as $tkey => &$tvalue) { // $tvalue -> $ivalue -> $t->testdata -> $inputdata -> $data // break any reference in that chain and the line below will not work $tvalue = strtoupper($tvalue); } foreach ($data as $dkey => $dvalue) { printf("%s: %s\n", $dkey, $dvalue); }

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