PHP IteratorAggregate又叫聚合式迭代器，它提供了创建外部迭代器的接口，接口摘要如下：

IteratorAggregate extends Traversable {
	abstract public Traversable getIterator ( void )
}

实现getIterator方法时必须返回一个实现了Iterator接口的类的实例。

例子说明：

<?php

class myData implements IteratorAggregate {
    public $one = "Public property one";
    public $two = "Public property two";
    public $three = "Public property three";
 
    public function __construct() {
        $this->last = "last property";
    }
 
    public function getIterator() {
        return new ArrayIterator($this);
    }
}
 
$obj = new myData;
 
foreach($obj as $key => $value) {
    var_dump($key, $value);
    echo '<br>';// Linux：echo "\n";
}

运行结果

string 'one' (length=3)
string 'Public property one' (length=19)

string 'two' (length=3)
string 'Public property two' (length=19)

string 'three' (length=5)
string 'Public property three' (length=21)

string 'last' (length=4)
string 'last property' (length=13)

原文链接：https://blog.csdn.net/wuxing26jiayou/article/details/51000301