(PECL ds >= 1.0.0)
Ds\Deque::copy — Returns a shallow copy of the deque
此函数没有参数。
A shallow copy of the deque.
Example #1 Ds\Deque::copy() example
<?php
$a = new \Ds\Deque([1, 2, 3]);
$b = $a->copy();
$b->push(4);
print_r($a);
print_r($b);
?>
以上例程的输出类似于：
Ds\Deque Object
(
[0] => 1
[1] => 2
[2] => 3
)
Ds\Deque Object
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
)