我有一个Foo类，我需要做：
$foo = new Foo();
foreach($foo as $value)
{
echo $value;
}
并定义我自己的方法来迭代这个对象，例如：
class Foo
{
private $bar = [1, 2, 3];
private $baz = [4, 5, 6];
function create_iterator()
{
//callback to the first creation of iterator for this object
$this->do_something_one_time();
}
function iterate()
{
//callback for each iteration in foreach
return $this->bar + $this->baz;
}
}
我们能做到吗？怎样
您需要实现''Iterator或''IteratorAggregate接口来实现这一点。
使用''IteratorAggregate和''Iterator接口（我省略了''Iterater实现的详细信息，但您可以使用PHP文档来查看它们的工作方式）来实现什么的一个简单示例：
class FooIterator implements 'Iterator
{
private $source = [];
public function __construct(array $source)
{
$this->source = $source;
// Do whatever else you need
}
public function current() { ... }
public function key() { ... }
public function next()
{
// This function is invoked on each step of the iteration
}
public function rewind() { ... }
public function valid() { ... }
}
class Foo implements 'IteratorAggregate
{
private $bar = [1, 2, 3];
private $baz = [4, 5, 6];
public function getIterator()
{
return new FooIterator(array_merge($this->bar, $this->baz));
}
}
$foo = new Foo();
foreach ($foo as $value) {
echo $value;
}