How to paginate an array

Short answer

array_slice() takes the needed portion: the offset is the page number minus one, multiplied by the page size:

<?php
 
$items = range(1, 23);
$page = 3;
$perPage = 5;
 
echo implode(', ', array_slice($items, ($page - 1) * $perPage, $perPage));

Output:

11, 12, 13, 14, 15

How many pages in total

Divide the count by the page size and round up:

<?php
 
$items = range(1, 23);
 
echo (int) ceil(count($items) / 5);

Output:

5

Data from a database

Only small arrays are paginated this way. Database records are cut by the query itself — LIMIT and OFFSET — so the whole table is not loaded into memory.