php 数组引用注意点

$b = [1,2,3];
foreach ($b as &$v){
    $v = 1;
}
var_dump($b);
$v = 2;
var_dump($b);

/* result
Array
(
    [0] => 1
    [1] => 1
    [2] => 1
)
Array
(
    [0] => 1
    [1] => 1
    [2] => 2
)
*/

数组循环引用的最后一个元素是引用，并与所引用变量名绑定在一起