php中foreach遍历类对象的总结

class my
{
	public $a = 'a';
	protected $b = 'b';
	private $c = 'c';
	private $data = array('fantasy','windows','linux');
	// 内部foreach遍历class
	function traversable()
	{
		foreach($this as $key=>$val)
		{
			echo $key.'=>';
			print_r($val);
			echo '<br>';
		}
	}
}
$m = new my();
// 外部foreach遍历class
foreach($m as $key=>$val)
{
	echo $key.'=>';
	print_r($val);
	echo '<br>';
}
echo '--------------------------<br>';
// 内部foreach遍历class
$m->traversable();

foreach($db->query('SELECT * FROM tab') as $row)
{
    print_r($row);
}

object(PDOStatement)#2 (1) {
  ["queryString"]=>
  string(18) "SELECT * FROM user"
}

class test implements Iterator
{
	public $a = 'a';
	private $data = array('apple','banlance','current');
	private $point = 0;
	public function __construct()
	{
		$this->point = 0;
	}
	public function current()
	{
		return $this->data[$this->point];
	}
	public function key()
	{
		return $this->point;
	}
	public function next()
	{
		++$this->point;
	}
	public function rewind()
	{
		$this->point=0;
	}
	public function valid()
	{
		return isset($this->data[$this->point]);
	}
}
$t = new test();
foreach($t as $val)
{
	print_r($val);
	echo '<br>';
}

// 迭代过程伪代码
while(valid)
{
<span style="white-space:pre">	</span>current/key
<span style="white-space:pre">	</span>next
}
rewind

test Object
(
    [a] => a
    [data:test:private] => Array
        (
            [0] => apple
            [1] => banlance
            [2] => current
        )
 
    [point:test:private] => 0
)