- var_export: documentation ( source)
<?php
function swapOutermost(&$a, $i = 0) {
$last = count($a) - 1 - $i;
if ($i < $last) {
[$a[$i], $a[$last]] = [$a[$last], $a[$i]];
swapOutermost($a, ++$i);
}
}
$array = [1, 2, 3, 4, 5, 6, 7];
swapOutermost($array);
var_export($array);