SPL提供了多个迭代器类，分别提供了迭代访问、过滤数据、缓存结果、控制分页等功能。，因为php总是在不断壮大，我尽可能列出SPL中所有的迭代类。下面其中一些迭代器类是需要php5.4，另外一些如SearhIteratoer类在最新的php版本中已经去除1.ArrayIteratoer从PHP数组创建一个迭代器，当其和IteratorAggregate类一起使用时，免去了直接实现Iterator接口的方法的工作。<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返回给定数量的结果以及从集合中取出结果的起始索引点：<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 按顺序迭代访问几个不同的迭代器。例如，希望在一次循环中迭代访问两个或者更多的组合。这个迭代器的append方法类似于array_merge()函数来合并数组。 $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$current."\n"; } /**output a b c d e f */ 4. FilterIterator基于OuterIterator接口，用于过滤数据，返回符合条件的元素。必须实现一个抽象方法accept()，此方法必须为迭代器的当前项返回true或false class UserFilter extends FilterIterator { private$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); //去除掉名为abdul的人员 $iterator = new UserFilter($object->getIterator(), 'abdul'); foreach ($iteratoras$result) { echo$result['name']; } /**output Jonathan **/ 5. RegexIterator继承FilterIterator，支持使用正则表达式模式匹配和修改迭代器中的元素。经常用于将字符串匹配。 $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一种通用类型的迭代器，所有实现了Traversable接口的类都可以被它迭代访问。7. CachingIterator用来执行提前读取一个元素的迭代操作，例如可以用于确定当前元素是否为最后一个元素。 $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用于创建非顺序访问的迭代器，允许跳转到迭代器中的任何一点上。 $array = array("apple", "banana", "cherry", "damson", "elderberry"); $iterator = new ArrayIterator($array); $iterator->seek(3); echo$iterator->current(); /**output damson **/ 9. NoRewindIterator用于不能多次迭代的集合，适用于在迭代过程中执行一次性操作。 $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一种占位符形式的迭代器，不执行任何操作。当要实现某个抽象类的方法并且这个方法需要返回一个迭代器时，可以使用这种迭代器。11. InfiniteIterator用于持续地访问数据，当迭代到最后一个元素时，会再次从第一个元素开始迭代访问。 $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创建一个用于递归形式数组结构的迭代器，类似于多维数组.它为许多更复杂的迭代器提供了所需的操作，如RecursiveTreeIterator和RecursiveIteratorIterator迭代器。 $fruits = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); $iterator = new RecursiveArrayIterator($fruits); while ($iterator->valid()) { //检查是否含有子节点 if ($iterator->hasChildren()) { //输出所以字节点 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将一个树形结构的迭代器展开为一维结构。 $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以可视在方式显示一个树形结构。 $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是一个扩展的FilterIterator迭代器，它可以过滤掉来自于RecursiveIterator迭代器的非父元素，只找出子节点的键值。通俗来说，就是去枝留叶。 $hey = array("a" => "lemon", "b" => "orange", array("a" => "apple", "p" => "pear")); $arrayIterator = new RecursiveArrayIterator($hey); $it = new ParentIterator($arrayIterator); print_r(iterator_to_array($it)); /**output Array ( [0] => Array ( [a] => apple [p] => pear ) ) **/ 16. RecursiveFilterIterator是FilterIterator迭代器的递归形式，也要求实现抽象的accept()方法，但在这个方法中应该使用$this->getInnerIterator()方法访问当前正在迭代的迭代器。 class TestsOnlyFilter extends RecursiveFilterIterator { publicfunction accept() { // 找出含有“叶”的元素 return$this->hasChildren() || (mb_strpos($this->current(), "叶") !== FALSE); } } $array = array("叶1", array("李2", "叶3", "叶4"), "叶5"); $iterator = new RecursiveArrayIterator($array); $filter = new TestsOnlyFilter($iterator); $filter = new RecursiveIteratorIterator($filter); print_r(iterator_to_array($filter)); /**output Array ( [0] => 叶1 [1] => 叶3 [2] => 叶5 ) **/ 17. RecursiveRegexIterator是RegexIterator迭代器的递归形式，只接受RecursiveIterator迭代器作为迭代对象。 $rArrayIterator = new RecursiveArrayIterator(array('叶1', array('tet3', '叶4', '叶5'))); $rRegexIterator = new RecursiveRegexIterator($rArrayIterator, '/^叶/', 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: 叶4 叶5 **/ 18. RecursiveCachingIterator在RecursiveIterator迭代器上执行提前读取一个元素的递归操作。 19. CallbackFilterIterator(PHP5.4)同时执行过滤和回调操作，在找到一个匹配的元素之后会调用回调函数。 $hey = array( "李1", "叶2", "叶3", "叶4", "叶5", "叶6",); $arrayIterator = new RecursiveArrayIterator($hey); function isYe($current) { return mb_strpos($current,'叶') !== false; } $rs = new CallbackFilterIterator($arrayIterator, 'isYe'); print_r(iterator_to_array($rs)); /**output Array ( [0] => 叶2 [1] => 叶3 [2] => 叶4 [3] => 叶5 [4] => 叶6 ) **/ 20. DirectoryIterator目录文件遍历器 方 法 描 述DirectoryIterator::getSize 得到文件大小DirectoryIterator::getType 得到文件类型DirectoryIterator::isDir 如果当前项是一个目录，返回trueDirectoryIterator::isDot 如果当前项是.或..，返回trueDirectoryIterator::isExecutable 如果文件可执行，返回trueDirectoryIterator::isFile 如果文件是一个常规文件，返回trueDirectoryIterator::isLink 如果文件是一个符号链接，返回trueDirectoryIterator::isReadable 如果文件可读，返回trueDirectoryIterator::isWritable 如果文件可写，返回trueDirectoryIterator::key 返回当前目录项DirectoryIterator::next 移动到下一项DirectoryIterator::rewind 将目录指针返回到开始位置DirectoryIterator::valid 检查目录中是否包含更多项 $it = new DirectoryIterator("../"); foreach ($itas$file) { //用isDot ()方法分别过滤掉“.”和“..”目录 if (!$it->isDot()) { echo$file . "\n"; } } 21. RecursiveDirectoryIterator递归目录文件遍历器，可实现列出所有目录层次结构，而不是只操作一个目录。 方 法 描 述RecursiveDirectoryIterator::getChildren 如果这是一个目录，为当前项返回一个迭代器RecursiveDirectoryIterator::hasChildren 返回当前项是否是一个目录而不是.或..RecursiveDirectoryIterator::key 返回当前目录项的路径和文件名RecursiveDirectoryIterator::next 移动到下一项RecursiveDirectoryIterator::rewind 将目录指针返回到开始位置RecursiveIteratorIterator::current 访问当前元素值RecursiveIteratorIterator::getDepth 得到递归迭代的当前深度RecursiveIteratorIterator::getSubIterator 得到当前活动子迭代器RecursiveIteratorIterator::key 访问当前键RecursiveIteratorIterator::next 前移到下一个元素RecursiveIteratorIterator::rewind 将迭代器返回到顶级内层迭代器的第一个元素RecursiveIteratorIterator::valid 检查当前位置是否合法 //列出指定目录中所有文件 $path = realpath('../'); $objects = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST); foreach ($objectsas$name => $object) { echo"$name\n"; } 22. FilesystemIterator是DirectoryIterator的遍历器 $it = new FilesystemIterator('../'); foreach ($itas$fileinfo) { echo$fileinfo->getFilename() . "\n"; } 23. GlobIterator带匹配模式的文件遍历器 //找出../目录中.php扩展名的文件 $iterator = new GlobIterator('./*.php'); if (!$iterator->count()) { echo'无php文件'; } else { $n = 0; printf("总计 %d 个php文件\r\n", $iterator->count()); foreach ($iteratoras$item) { printf("[%d] %s\r\n", ++$n, $iterator->key()); } } /**output 总计 23 个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用于迭代器的连接器，具体看示例 $person_id = new ArrayIterator(array('001', '002', '003')); $person_name = new ArrayIterator(array('张三', '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"连接的迭代器个数:".$mit->countIterators() . "\n"; //3 foreach ($mitas$person) { print_r($person); } /**output Array ( [ID] => 001 [NAME] => 张三 [AGE] => 22 ) Array ( [ID] => 002 [NAME] => 李四 [AGE] => 23 ) Array ( [ID] => 003 [NAME] => 王五 [AGE] => 11 ) **/ 25. RecursiveCallbackFilterIterator(PHP5.4)在RecursiveIterator迭代器上进行递归操作，同时执行过滤和回调操作，在找到一个匹配的元素之后会调用回调函数。 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. SimpleXMLIteratorXMl文档访问迭代器，可实现访问xml中所有节点 $xml = <<<XML <books> <book> <title>PHP Basics</title> <author>Jim Smith</author> </book> <book>XML basics</book> </books> XML; // SimpleXML转换为数组 function sxiToArray($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 ) ) **/ 登录后复制
