php - PHP OOP 中 $a=&$b 、 $a = $b 和 $a= clone $b 的区别

Question

PHP 中$a = &$b、$a = $b 和$b = clone $a 有什么区别面向对象？ $a 是一个类的实例。

Answer 1

// $a is a reference of $b, if $a changes, so does $b.    
$a = &$b; 

// assign $b to $a, the most basic assign.
$a = $b; 

// This is for object clone. Assign a copy of object `$b` to `$a`. 
// Without clone, $a and $b has same object id, which means they are pointing to same object.
$a = clone $b; 

并使用 References 查看更多信息, Object Cloning .