You could use a mix of functions, avoiding loops:
$keys = array_flip(range(14,30)); $result = array_intersect_key($entry, $keys);
range() generates an array with the indices you want to compare against.
array_flip() turns the so generated array values into array keys, since you want to intersect array keys.
array_intersect_key does what you need basically.
The above example could be written also as oneliner, but... you know readability and that ;)