How to "cut" my array to a shorter length?

Check out array_slice()

So, if you wanted the first three elements only:

$array = array_slice($array, 0, 3);

If you wanted all but the last three elements:

$array = array_slice($array, 0, -3);

The second parameter is the start point (0 means to start from the begining of the array).

The third parameter is the length of the resulting array. From the documentation:

If length is given and is positive, then the sequence will have that many elements in it. If length is given and is negative then the sequence will stop that many elements from the end of the array. If it is omitted, then the sequence will have everything from offset up until the end of the array.

http://dev.fyicenter.com/faq/php/php_array_function_6.php

Look at the one about truncating, particularly array_splice