Swap¶
Swap may be two things:
Memory, stored on the disk.
The operation to exchange two things, one for another. For example, variable swap, which exchange their value.
<?php
// simple swap technique :
// list and array are used for readability
list($a, $b) = array($a, $b);
// modern version
[$a, $b] = [$a, $b];
?>
