- range: documentation ( source)
<?php
$count = 5;
$last = 4;
foreach (range(-5, 4, 1) as $v) {
if ($v < 0) {
print $v . ': ' .$v % $count . ' ' . ((($v % $count) + $count) % $count + 1) . "\n";
} else {
print $v . ': ' .$v % $count . ' ' . (($v % $count) + $count) % $count . "\n";
}
}