If you call array_values on your array, it will be reindexed from zero.
array_values
If you are using Array filter do it as follows
$NewArray = array_values(array_filter($OldArray));
Use array_values():
array_values()
<?php$array = array('foo', 'bar', 'baz');$array = array_filter($array, function ($var) { return $var !== 'bar';});print_r($array); // indexes 0 and 2print_r(array_values($array)); // indexes 0 and 1