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<?php $row = array( 'useless' => 42, 'useful' => 'orange', 'useless_too' => 'banana', 'useful_too' => 'apples'); foreach ($row as $key1=>$value){ $pos = strpos($key1,'useful'); if($pos==-1) unset($row[$key]); } print_r($row);

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39.41 ms | 402 KiB | 5 Q