(PECL ds >= 1.0.0)
Ds\Set::sort — Sorts the set in-place
Sorts the set in-place, using an optional comparator function.
comparator在第一个参数小于，等于或大于第二个参数时，该比较函数必须相应地返回一个小于，等于或大于 0 的整数。
Returning non-integer values from the comparison function, such as float, will result in an internal cast to int of the callback's return value. So values such as 0.99 and 0.1 will both be cast to an integer value of 0, which will compare such values as equal.
没有返回值。
Example #1 Ds\Set::sort() example
<?php
$set = new \Ds\Set([4, 5, 1, 3, 2]);
$set->sort();
print_r($set);
?>
以上例程的输出类似于：
Ds\Set Object
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)
Example #2 Ds\Set::sort() example using a comparator
<?php
$set = new \Ds\Set([4, 5, 1, 3, 2]);
$set->sort(function($a, $b) {
return $b <=> $a;
});
print_r($set);
?>
以上例程的输出类似于：
Ds\Set Object
(
[0] => 5
[1] => 4
[2] => 3
[3] => 2
[4] => 1
)