php-SPL庫迭代器類

SPL提供了多個迭代器類，分別提供了迭代訪問、過濾數據、緩存結果、控制分頁等功能。，由於php老是在不斷壯大，我儘量列出SPL中全部的迭代類。下面其中一些迭代器類是須要php5.4，另一些如SearhIteratoer類在最新的php版本中已經去除

1.ArrayIteratoer

從PHP數組建立一個迭代器，當其和IteratorAggregate類一塊兒使用時，免去了直接實現Iterator接口的方法的工做。

<示例>

$b = array( 

    'name'=> 'mengzhi', 

    'age' => '12', 

    'city'=> 'shanghai' 

); 

$a = new ArrayIterator($b); 

$a->append(array( 

                'home' => 'china', 

                'work' => 'developer' 

           )); 

$c = $a->getArrayCopy(); 

print_r($a); 

print_r($c); 

 

/**output

ArrayIterator Object

(

    [storage:ArrayIterator:private] => Array

    (

    [name] => mengzhi

            [age] => 12

            [city] => shanghai

            [0] => Array

    (

    [home] => china

                    [work] => developer

                )


        )


)

Array

    (

    [name] => mengzhi

    [age] => 12

    [city] => shanghai

    [0] => Array

    (

    [home] => china

            [work] => developer

        )


)

**/

2. LimitIterator

返回給定數量的結果以及從集合中取出結果的起始索引點：

<示例>

// Create an iterator to be limited 

$fruits = new ArrayIterator(array( 

                                 'apple', 

                                 'banana', 

                                 'cherry', 

                                 'damson', 

                                 'elderberry' 

                            )); 

// Loop over first three fruits only 

foreach (new LimitIterator($fruits, 0, 3) as$fruit) { 

    var_dump($fruit); 

} 

echo"\n"; 

// Loop from third fruit until the end 

// Note: offset starts from zero for apple 

foreach (new LimitIterator($fruits, 2) as$fruit) { 

    print_r($fruit); 

} 

 

/**output

string(5) "apple"

string(6) "banana"

string(6) "cherry"


cherrydamsonelderberry

 */

3. AppendIterator

按順序迭代訪問幾個不一樣的迭代器。例如，但願在一次循環中迭代訪問兩個或者更多的組合。這個迭代器的append方法相似於array_merge()函數來合併數組。

$array_a = new ArrayIterator(array('a', 'b', 'c')); 

$array_b = new ArrayIterator(array('d', 'e', 'f')); 

$iterator = new AppendIterator; 

$iterator->append($array_a); 

$iterator->append($array_b); 

foreach ($iteratoras$current) { 

    echo$current."\n"; 

} 

/**output

a

b

c

d

e

f

 */

4. FilterIterator

基於OuterIterator接口，用於過濾數據，返回符合條件的元素。必須實現一個抽象方法accept()，此方法必須爲迭代器的當前項返回true或false

class UserFilter extends FilterIterator 

{ 

    private$userFilter; 

 

    publicfunction __construct(Iterator $iterator, $filter) 

    { 

        parent::__construct($iterator); 

        $this->userFilter = $filter; 

    } 

 

    publicfunction accept() 

    { 

        $user = $this->getInnerIterator()->current(); 

        if (strcasecmp($user['name'], $this->userFilter) == 0) { 

            return false; 

        } 

        return true; 

    } 

} 

 

$array = array( 

    array( 

        'name' => 'Jonathan', 

        'id'   => '5' 

    ), 

    array( 

        'name' => 'Abdul', 

        'id'   => '22' 

    ) 

); 

$object = new ArrayObject($array); 

//去除掉名爲abdul的人員 

$iterator = new UserFilter($object->getIterator(), 'abdul'); 

foreach ($iteratoras$result) { 

    echo$result['name']; 

} 

 

/**output

Jonathan

**/

5. RegexIterator

繼承FilterIterator，支持使用正則表達式模式匹配和修改迭代器中的元素。常常用於將字符串匹配。

$a = new ArrayIterator(array('test1', 'test2', 'test3')); 

$i = new RegexIterator($a, '/^(test)(\d+)/', RegexIterator::REPLACE); 

$i->replacement = '$2:$1'; 

print_r(iterator_to_array($i)); 

 

/**output

Array

(

    [0] => 1:test

    [1] => 2:test

    [2] => 3:test

)

 **/

6. IteratorIterator

一種通用類型的迭代器，全部實現了Traversable接口的類均可以被它迭代訪問。

7. CachingIterator

用來執行提早讀取一個元素的迭代操做，例如能夠用於肯定當前元素是否爲最後一個元素。

$array = array('koala', 'kangaroo', 'wombat', 'wallaby', 'emu', 'kiwi', 'kookaburra', 'platypus'); 

try { 

    $object = new CachingIterator(new ArrayIterator($array)); 

    foreach ($objectas$value) { 

        echo$value; 

        if ($object->hasNext()) { 

            echo','; 

        } 

    } 

} 

catch (Exception $e) { 

    echo$e->getMessage(); 

} 

/**output

koala,kangaroo,wombat,wallaby,emu,kiwi,kookaburra,platypus

 **/

8. SeekableIterator

用於建立非順序訪問的迭代器，容許跳轉到迭代器中的任何一點上。

$array = array("apple", "banana", "cherry", "damson", "elderberry"); 

$iterator = new ArrayIterator($array); 

$iterator->seek(3); 

echo$iterator->current(); 

/**output

damson

 **/

9. NoRewindIterator

用於不能屢次迭代的集合，適用於在迭代過程當中執行一次性操做。

$fruit = array('apple', 'banana', 'cranberry'); 

$arr = new ArrayObject($fruit); 

$it = new NoRewindIterator($arr->getIterator()); 

echo"Fruit A:\n"; 

foreach ($itas$item) { 

    echo$item . "\n"; 

} 

 

echo"Fruit B:\n"; 

foreach ($itas$item) { 

    echo$item . "\n"; 

} 

/**output

Fruit A:

apple

banana

cranberry

Fruit B:

 **/

10. EmptyIterator

一種佔位符形式的迭代器，不執行任何操做。當要實現某個抽象類的方法而且這個方法須要返回一個迭代器時，能夠使用這種迭代器。

11. InfiniteIterator

用於持續地訪問數據，當迭代到最後一個元素時，會再次從第一個元素開始迭代訪問。

$arrayit = new ArrayIterator(array('cat', 'dog')); 

$infinite = new InfiniteIterator($arrayit); 

$limit = new LimitIterator($infinite, 0, 7); 

foreach ($limitas$value) { 

    echo"$value\n"; 

} 

/**output

cat

dog

cat

dog

cat

dog

cat

 **/

12. RecursiveArrayIterator

建立一個用於遞歸形式數組結構的迭代器，相似於多維數組.它爲許多更復雜的迭代器提供了所需的操做，如RecursiveTreeIterator和RecursiveIteratorIterator迭代器。

$fruits = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); 

$iterator = new RecursiveArrayIterator($fruits); 

while ($iterator->valid()) { 

    //檢查是否含有子節點 

    if ($iterator->hasChildren()) { 

        //輸出因此字節點 

        foreach ($iterator->getChildren() as$key => $value) { 

            echo$key . ' : ' . $value . "\n"; 

        } 

    } else { 

        echo"No children.\n"; 

    } 

    $iterator->next(); 

} 

 

/**output

No children.

No children.

a : apple

p : pear

 **/

13. RecursiveIteratorIterator

將一個樹形結構的迭代器展開爲一維結構。

$fruits = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); 

$arrayiter = new RecursiveArrayIterator($fruits); 

$iteriter = new RecursiveIteratorIterator($arrayiter); 

foreach ($iteriteras$key => $value) { 

    $d = $iteriter->getDepth(); 

    echo"depth=$d k=$key v=$value\n"; 

} 

 

/**output

depth=0 k=a v=lemon

depth=0 k=b v=orange

depth=1 k=a v=apple

depth=1 k=p v=pear

 **/

14. RecursiveTreeIterator

以可視在方式顯示一個樹形結構。

$hey = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); 

$awesome = new RecursiveTreeIterator( 

    new RecursiveArrayIterator($hey), 

    null, null, RecursiveIteratorIterator::LEAVES_ONLY 

); 

foreach ($awesomeas$line) 

    echo$line . PHP_EOL; 

 

/**output

|-lemon

|-orange

    |-apple

    \-pear

 **/

15. ParentIterator

是一個擴展的FilterIterator迭代器，它能夠過濾掉來自於RecursiveIterator迭代器的非父元素，只找出子節點的鍵值。通俗來講，就是去枝留葉。

$hey = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); 

$arrayIterator = new RecursiveArrayIterator($hey); 

$it = new ParentIterator($arrayIterator); 

print_r(iterator_to_array($it)); 

/**output

Array

    (

    [0] => Array

    (

        [a] => apple

        [p] => pear

    )

)

 **/

16. RecursiveFilterIterator

是FilterIterator迭代器的遞歸形式，也要求實現抽象的accept()方法，但在這個方法中應該使用$this->getInnerIterator()方法訪問當前正在迭代的迭代器。

class TestsOnlyFilter extends RecursiveFilterIterator 

{ 

    publicfunction accept() 

    { 

        // 找出含有「葉」的元素 

        return$this->hasChildren() || (mb_strpos($this->current(), "葉") !== FALSE); 

    } 

} 

 

$array = array("葉1", array("李2", "葉3", "葉4"), "葉5"); 

$iterator = new RecursiveArrayIterator($array); 

$filter = new TestsOnlyFilter($iterator); 

$filter = new RecursiveIteratorIterator($filter); 

print_r(iterator_to_array($filter)); 

/**output

Array

(

    [0] => 葉1

    [1] => 葉3

    [2] => 葉5

)

**/

17. RecursiveRegexIterator

是RegexIterator迭代器的遞歸形式，只接受RecursiveIterator迭代器做爲迭代對象。

$rArrayIterator = new RecursiveArrayIterator(array('葉1', array('tet3', '葉4', '葉5'))); 

$rRegexIterator = new RecursiveRegexIterator($rArrayIterator, '/^葉/', 

    RecursiveRegexIterator::ALL_MATCHES); 

 

foreach ($rRegexIteratoras$key1 => $value1) { 

    if ($rRegexIterator->hasChildren()) { 

        // print all children 

        echo"Children: "; 

        foreach ($rRegexIterator->getChildren() as$key => $value) { 

            echo$value . " "; 

        } 

        echo"\n"; 

    } else { 

        echo"No children\n"; 

    } 

} 

/**output

No children

Children: 葉4 葉5 

 **/

18. RecursiveCachingIterator

在RecursiveIterator迭代器上執行提早讀取一個元素的遞歸操做。

19. CallbackFilterIterator(PHP5.4)

同時執行過濾和回調操做，在找到一個匹配的元素以後會調用回調函數。

$hey = array( "李1", "葉2", "葉3", "葉4", "葉5", "葉6",); 

$arrayIterator = new RecursiveArrayIterator($hey); 

function isYe($current) 

{ 

    return mb_strpos($current,'葉') !== false; 

} 

 

$rs = new CallbackFilterIterator($arrayIterator, 'isYe'); 

print_r(iterator_to_array($rs)); 

 

/**output

Array

(

    [0] => 葉2

    [1] => 葉3

    [2] => 葉4

    [3] => 葉5

    [4] => 葉6

)

 **/

20. DirectoryIterator

目錄文件遍歷器

方 法

描 述

DirectoryIterator::getSize

獲得文件大小

DirectoryIterator::getType

獲得文件類型

DirectoryIterator::isDir

若是當前項是一個目錄，返回true

DirectoryIterator::isDot

若是當前項是.或..，返回true

DirectoryIterator::isExecutable

若是文件可執行，返回true

DirectoryIterator::isFile

若是文件是一個常規文件，返回true

DirectoryIterator::isLink

若是文件是一個符號連接，返回true

DirectoryIterator::isReadable

若是文件可讀，返回true

DirectoryIterator::isWritable

若是文件可寫，返回true

DirectoryIterator::key

返回當前目錄項

DirectoryIterator::next

移動到下一項

DirectoryIterator::rewind

將目錄指針返回到開始位置

DirectoryIterator::valid

檢查目錄中是否包含更多項

$it = new DirectoryIterator("../"); 

foreach ($itas$file) { 

    //用isDot ()方法分別過濾掉「.」和「..」目錄 

    if (!$it->isDot()) { 

        echo$file . "\n"; 

    } 

}

21. RecursiveDirectoryIterator

遞歸目錄文件遍歷器，可實現列出全部目錄層次結構，而不是隻操做一個目錄。

方 法

描 述

RecursiveDirectoryIterator::getChildren

若是這是一個目錄，爲當前項返回一個迭代器

RecursiveDirectoryIterator::hasChildren

返回當前項是不是一個目錄而不是.或..

RecursiveDirectoryIterator::key

返回當前目錄項的路徑和文件名

RecursiveDirectoryIterator::next

移動到下一項

RecursiveDirectoryIterator::rewind

將目錄指針返回到開始位置

RecursiveIteratorIterator::current

訪問當前元素值

RecursiveIteratorIterator::getDepth

獲得遞歸迭代的當前深度

RecursiveIteratorIterator::getSubIterator

獲得當前活動子迭代器

RecursiveIteratorIterator::key

訪問當前鍵

RecursiveIteratorIterator::next

前移到下一個元素

RecursiveIteratorIterator::rewind

將迭代器返回到頂級內層迭代器的第一個元素

RecursiveIteratorIterator::valid

檢查當前位置是否合法

//列出指定目錄中全部文件 

$path = realpath('../'); 

$objects = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST); 

foreach ($objectsas$name => $object) { 

    echo"$name\n"; 

}

22. FilesystemIterator

是DirectoryIterator的遍歷器

$it = new FilesystemIterator('../'); 

foreach ($itas$fileinfo) { 

    echo$fileinfo->getFilename() . "\n"; 

}

23. GlobIterator

帶匹配模式的文件遍歷器

//找出../目錄中.php擴展名的文件 

$iterator = new GlobIterator('./*.php'); 

if (!$iterator->count()) { 

    echo'無php文件'; 

} else { 

    $n = 0; 

    printf("總計 %d 個php文件\r\n", $iterator->count()); 

    foreach ($iteratoras$item) { 

        printf("[%d] %s\r\n", ++$n, $iterator->key()); 

    } 

} 

/**output 

總計 23 個php文件 

[1] .\1.php 

[2] .\11.php 

[3] .\12.php 

[4] .\13.php 

[5] .\14.php 

[6] .\15.php 

[7] .\16.php 

[8] .\17.php 

[9] .\19.php 

[10] .\2.php 

[11] .\20.php 

[12] .\21.php 

[13] .\22.php 

[14] .\23.php 

[15] .\24.php 

[16] .\25.php 

[17] .\26.php 

[18] .\3.php 

[19] .\4.php 

[20] .\5.php 

[21] .\7.php 

[22] .\8.php 

[23] .\9.php 

**/

24. MultipleIterator

用於迭代器的鏈接器，具體看示例

$person_id = new ArrayIterator(array('001', '002', '003')); 

$person_name = new ArrayIterator(array('張三', '李四', '王五')); 

$person_age = new ArrayIterator(array(22, 23, 11)); 

$mit = new MultipleIterator(MultipleIterator::MIT_KEYS_ASSOC); 

$mit->attachIterator($person_id, "ID"); 

$mit->attachIterator($person_name, "NAME"); 

$mit->attachIterator($person_age, "AGE"); 

echo"鏈接的迭代器個數:".$mit->countIterators() . "\n"; //3 

foreach ($mitas$person) { 

    print_r($person); 

} 

/**output

Array

(

    [ID] => 001

    [NAME] => 張三

    [AGE] => 22

)

Array

(

    [ID] => 002

    [NAME] => 李四

    [AGE] => 23

)

Array

(

    [ID] => 003

    [NAME] => 王五

    [AGE] => 11

)

 **/

25. RecursiveCallbackFilterIterator(PHP5.4)

在RecursiveIterator迭代器上進行遞歸操做，同時執行過濾和回調操做，在找到一個匹配的元素以後會調用回調函數。

function doesntStartWithLetterT($current) 

{ 

    $rs = $current->getFileName(); 

    return$rs[0] !== 'T'; 

} 

 

$rdi = new RecursiveDirectoryIterator(__DIR__); 

$files = new RecursiveCallbackFilterIterator($rdi, 'doesntStartWithLetterT'); 

foreach (new RecursiveIteratorIterator($files) as$file) { 

    echo$file->getPathname() . PHP_EOL; 

}

26. SimpleXMLIterator

XMl文檔訪問迭代器，可實現訪問xml中全部節點

$xml = <<<XML 

<books> 

    <book> 

        <title>PHP Basics</title> 

        <author>Jim Smith</author> 

    </book> 

    <book>XML basics</book> 

</books> 

XML; 

// SimpleXML轉換爲數組 

function sxiToArray($sxi) 

{ 

    $a = array(); 

    for ($sxi->rewind(); $sxi->valid(); $sxi->next()) { 

        if (!array_key_exists($sxi->key(), $a)) { 

            $a[$sxi->key()] = array(); 

        } 

        if ($sxi->hasChildren()) { 

            $a[$sxi->key()][] = sxiToArray($sxi->current()); 

        } else { 

            $a[$sxi->key()][] = strval($sxi->current()); 

        } 

    } 

    return$a; 

} 

 

$xmlIterator = new SimpleXMLIterator($xml); 

$rs = sxiToArray($xmlIterator); 

print_r($rs); 

/**output

Array

(

    [book] => Array

        (

            [0] => Array

                (

                    [title] => Array

                        (

                            [0] => PHP Basics

                        )


                    [author] => Array

                        (

                            [0] => Jim Smith

                        )


                )


            [1] => XML basics

        )


)

 **/