foreach ($entity_array as $entPhysicalIndex => $entry) {
    $entPhysicalIndex = array_key_exists('entPhysicalIndex', $entry) ? $entry['entPhysicalIndex'] : '';
    $entPhysicalDescr = array_key_exists('entPhysicalDescr', $entry) ? $entry['entPhysicalDescr'] : '';
    $entPhysicalClass = array_key_exists('entPhysicalClass', $entry) ? $entry['entPhysicalClass'] : '';
    $entPhysicalName = array_key_exists('entPhysicalName', $entry) ? $entry['entPhysicalName'] : '';