Learn And Life.

迭代器一二

Posted on

php当中有许多迭代器，但是日常的编程当中可能会很少使用，一方面是因为迭代的功能有限，只能在有限的对象集中使用，另一方面还是面向对象的思想的匮乏，下面看看php当中的一些迭代器

迭代器接口

1
2
3
4
5
6
7
interface Iterator {
    function rewind();
    function current();
    function key();
    function next();
    function valid();
}

php中的迭代器的应用

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
ArrayIterator implements ArrayAccess , SeekableIterator , Countable , Serializable
AppendIterator extends IteratorIterator implements OuterIterator
CachingIterator extends IteratorIterator implements OuterIterator , ArrayAccess , Countable 
CallbackFilterIterator extends FilterIterator implements OuterIterator
DirectoryIterator extends SplFileInfo implements SeekableIterator
EmptyIterator implements Iterator
FilesystemIterator extends DirectoryIterator implements SeekableIterator
abstract FilterIterator extends IteratorIterator implements OuterIterator
GlobIterator extends FilesystemIterator implements SeekableIterator , Countable
InfiniteIterator extends IteratorIterator implements OuterIterator
IteratorIterator implements OuterIterator
LimitIterator extends IteratorIterator implements OuterIterator
MultipleIterator implements Iterator
NoRewindIterator extends IteratorIterator 
ParentIterator extends RecursiveFilterIterator implements RecursiveIterator , OuterIterator
RecursiveArrayIterator extends ArrayIterator implements RecursiveIterator 
RecursiveCachingIterator extends CachingIterator implements Countable , ArrayAccess , OuterIterator , RecursiveIterator
RecursiveCallbackFilterIterator extends CallbackFilterIterator implements OuterIterator , RecursiveIterator
RecursiveDirectoryIterator extends FilesystemIterator implements SeekableIterator , RecursiveIterator
abstract RecursiveFilterIterator extends FilterIterator implements OuterIterator , RecursiveIterator
RecursiveIteratorIterator implements OuterIterator
RecursiveRegexIterator extends RegexIterator implements RecursiveIterator
RecursiveTreeIterator extends RecursiveIteratorIterator implements OuterIterator
RegexIterator extends FilterIterator

应用举例，遍历目录下面的所有指定后缀的文件

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
class  RecursiveFileFilterIterator extends FilterIterator{
	protected $ext = array('jpg','png','php');
	public function __construct($path){
		parent::__construct(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path)));
	}
	public function accept(){
		$item = $this->getInnerIterator();
		if($item->isFile() && in_array(pathinfo($item->getFilename(),PATHINFO_EXTENSION), $this->ext)){
			return true;
		}
	}
}
foreach(new RecursiveFileFilterIterator('/Users/kivmi/Documents') as $item){
	echo $item.PHP_EOL;
}

迭代设计模式

1.创建迭代器

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
 namespace platform;
class  PlatformIteratorBlock implements  \Iterator
{
    protected  $current = 0;
    protected  $platformList = null;
    public  function __construct(PlatformBlocks $platformList)
    {
        $this->platformList = $platformList;
        $this->current = $this->platformList->count() - 1;
    }
    public  function  current()
    {
        return $this->platformList->get($this->current);
    }
    public  function key()
    {
        return $this->current;
    }
    public  function next()
    {
        $this->current -- ;
    }
    public  function rewind()
    {
        $this->current = $this->platformList->count() - 1;
    }
    public  function valid( )
    {
        return null != $this->platformList->get($this->current);
    }
}

2.创建一个篮子

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
namespace platform;
class PlatformBlocks implements  \Countable
{
    protected  $platforms =  [];
    public  function get($n)
    {
            if(isset($this->platforms[$n]))
            {
                    return $this->platforms[$n];
            }
            return null;
    }
    public function add(PlatformBlock $platform)
    {
            $this->platforms[]  = $platform;
    }
    public function remove(PlatformBlock $platform)
    {
            foreach ($this->platforms as $k => $block)
            {
                 if($block->getName()  == $platform->getName())
                 {
                        unset($this->platforms[$k]);
                 }
            }
    }
    public function count()
    {
            return  count($this->platforms);
    }
}

3.从篮子里消费

1
2
3
4
5
6
7
8
9
10
11
12
$platformList = new PlatformListBlock();
$platformList->add(new NewsPlatformBlock());
$iterator = new PlatformIteratorBlock($platformList);
while($iterator->valid())
{
   foreach ($iterator->current()->getData() as $params)
   {
       self::doRequest($iterator->current()->getUrl(), $params);
   }
   $iterator->next();
}}