Cache

Cache, or caching, is a technique used to store and reuse the results of expensive operations to improve performance.

There are different types of caches, depending on where they are applied: opcode cache, data cache, query cache, etc.

<?php

    $count = count($array);
    // $count is a cache for the number of elements in the array
    // it saves a call to count() for every loop

    for($i = 0; $i < $count; ++$i) {
        doSomething($i);
    }

?>

Documentation

See Also

PHP cache