class MainIterator implements Iterator
{
    private $var = array();
    public function __construct($array)    //構(gòu)造函數(shù), 初始化對(duì)象數(shù)組
    {
        if (is_array($array)) {
        $this->var = $array;
        }
    }
 
    public function rewind() {   
        echo "rewinding\n";
        reset($this->var);    //將數(shù)組的內(nèi)部指針指向第一個(gè)單元
    }
 
    public function current() {
        $var = current($this->var);    // 返回?cái)?shù)組中的當(dāng)前值
        echo "current: $var\n";
        return $var;
    }
 
    public function key() {
        $var = key($this->var);       //返回?cái)?shù)組中內(nèi)部指針指向的當(dāng)前單元的鍵名
        echo "key: $var\n";
        return $var;
    }
 
    public function next() {
        $var = next($this->var);     //返回?cái)?shù)組內(nèi)部指針指向的下一個(gè)單元的值
        echo "next: $var\n";
        return $var;
    }
 
    public function valid() {
    return !is_null(key($this->var); //判斷當(dāng)前單元的鍵是否為空
    }
}

<?php
class myData implements IteratorAggregate {
    public $property1 = "Public property one";
    public $property2 = "Public property two";
    public $property3 = "Public property three";

    public function __construct() {
        $this->property4 = "last property";
    }

    public function getIterator() {
        return new ArrayIterator($this);
    }
}

$obj = new myData;

foreach($obj as $key => $value) {
    var_dump($key, $value);
    echo "\n";
}
?>