Online PHP editor | refs for 5mnAt

<?php $array = array(); echo PHP_EOL . ' on empty array: ' . PHP_EOL; var_dump(key($array)); $array[] = 'f'; echo PHP_EOL . ' size one array: ' . PHP_EOL; var_dump(key($array)); $array[] = 'f'; echo PHP_EOL . ' size two array: ' . PHP_EOL; var_dump(key($array)); echo PHP_EOL . ' within loop: ' . PHP_EOL; foreach ($array as $key => $value) { var_dump(key($array)); if ($key == 1) { echo PHP_EOL . ' unsetting second element.... ' . PHP_EOL; unset($array[$key]); } } var_dump($array); echo PHP_EOL . ' after loop: ' . PHP_EOL; var_dump(key($array)); var_dump(current($array)); reset($array); echo PHP_EOL . ' after reset: ' . PHP_EOL; var_dump(key($array)); var_dump(current($array)); end($array); echo PHP_EOL . ' after end: ' . PHP_EOL; var_dump(key($array)); var_dump(current($array)); echo PHP_EOL . ' trying to trigger "Undefined index: " error: with NULL key' . PHP_EOL; $array[null]; echo PHP_EOL . ' trying to trigger "Undefined index: " error: with empty string key' . PHP_EOL; $array[''];