Re-using variables which where references before, without unsetting them first, leads to unexpected behaviour.
The following code:
<?php
$numbers = array();
for ($i = 1; $i < 4; $i++) {
$numbers[] = null;
$num = count($numbers);
$index =& $numbers[$num ? $num - 1 : $num];
$index = $i;
}
foreach ($numbers as $index) {
print "$index\n";
}
?>
Does not produce:
1
2
3
But instead:
1
2
2
Applying unset($index) before re-using the variable fixes this and the expected list will be produced:
1
2
3
