unset() bug or feature?

Mostly used to Perl, the result of the following code snippet makes me a bit confused. I understand PHP makes no difference between arrays and hashes, but in this case if feels somewhat awkward. Traversing $array, unsetting each value, adding new values, renders an array which doesn't start at index 0. Shouldn't unset() really unset the entry, making the internal array pointer point to the next free place in $array (i.e. the place of the just unset() entry)? In other words, if I unset() $array[0], why doesn't the subsequent $array[] = "entry_$i" put "entry_$i" at $array[0]? $array = array("entry_0", "entry_1"); $array_count = count($array); for ($i=0;$i<$array_count;$i++) { unset ($array[$i]); $array[] = "entry_$i"; } print "<P>count(\$array) = " . count($array); print "<P>"; for ($i=0;$i<=3;$i++) { print "\$array[$i] = $array[$i]<BR>"; } Result: count($array) = 2 $array[0] = $array[1] = $array[2] = entry_0 $array[3] = entry_1 Best regards, /Johan Ekenberg