Filtering and sorting
Filter selects values; sorting changes their order.
What it is
Filter selects values; sorting changes their order.
When to use it
Use for small in-memory lists, not entire large database tables.
Syntax
$active = array_values(array_filter($users, fn ($u) => $u["active"]));
usort($active, fn ($a, $b) => $a["name"] <=> $b["name"]);Example
$users = [["name" => "Lin", "active" => true], ["name" => "Ada", "active" => true]];
$active = array_values(array_filter($users, fn ($u) => $u["active"]));
usort($active, fn ($a, $b) => strcmp($a["name"], $b["name"]));Common mistakes
usort mutates and reindexes; array_filter without a callback drops zero and false.