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php遍历对象数据 php遍历结果集( 二 )

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PHP手册预定义接口部分指出：要实现迭代器模式，需要在可迭代对象中实现如下接口：
[php] view plaincopy
abstractpublicmixedcurrent( void )
abstractpublicscalarkey( void )
abstractpublicvoidnext( void )
abstractpublicvoidrewind( void )
abstractpublicbooleanvalid( void )
有了这个 。实现迭代器模式就很方便了，一个简单的实例如下：
[php] view plaincopy
class TestIterator implements Iterator {
private $point = 0;
private $data = https://www.04ip.com/post/array(
"one","two","three",
);
public function __construct() {
$this-point = 0;
}
function rewind() {
$this-point = 0;
}
function current() {
return $this-data[$this-point];
}
function key() {
return $this-point;
}
function next() {
++$this-point;
}
function valid() {
return isset($this-data[$this-point]);
}
}
$it = new TestIterator;
foreach($it as $key = $value) {
echo $key, $value;
echo "\n";
}
当然，使用了迭代器的对象可以以如下方式进行遍历：
[php] view plaincopy
$it = new TestIterator;
$it-rewind();
while ($it-valid()){
$key = $it-key();
$value = https://www.04ip.com/post/$it-current();
echo "$key=$value";
$it-next();
}
最后附上YII中ListIterator（顾名思义，实现对List的迭代操作的迭代器）的实现：
[php] view plaincopy
?php
/**
* CListIterator class file.
*
* @author Qiang Xue qiang.xue@gmail.com
* @link
* @copyright Copyright ? 2008-2011 Yii Software LLC
* @license
*/
/**
* CListIterator implements an interator for {@link CList}.
*
* It allows CList to return a new iterator for traversing the items in the list.
*
* @author Qiang Xue qiang.xue@gmail.com
* @version $Id$
* @package system.collections
* @since 1.0
*/
class CListIterator implements Iterator
{
/**
* @var array the data to be iterated through
*/
private $_d;
/**
* @var integer index of the current item
*/
private $_i;
/**
* @var integer count of the data items
*/
private $_c;
/**
* Constructor.
* @param array $data the data to be iterated through
*/
public function __construct($data)
{
$this-_d=$data;
$this-_i=0;
$this-_c=count($this-_d);
}
/**
* Rewinds internal array pointer.
* This method is required by the interface Iterator.
*/
public function rewind()
{
$this-_i=0;
}
/**
* Returns the key of the current array item.
* This method is required by the interface Iterator.
* @return integer the key of the current array item
*/
public function key()
{
return $this-_i;
}
/**
* Returns the current array item.
* This method is required by the interface Iterator.
* @return mixed the current array item
*/
public function current()
{
return $this-_d[$this-_i];
}
/**
* Moves the internal pointer to the next array item.
* This method is required by the interface Iterator.
*/
public function next()
{
$this-_i++;
}
/**
* Returns whether there is an item at current position.
* This method is required by the interface Iterator.
* @return boolean
*/
public function valid()
{
return $this-_i$this-_c;
}
}
PHP 数组遍历方法大全(foreach,list,each)在PHP中数组分为两类：
数字索引数组和关联数组 。
其中数字索引数组和C语言中的数组一样，下标是为0，1 ， 2…

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