Php/docs/class.iterator

PHP Manual
预定义接口
Iterator（迭代器）接口

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简介

可在内部迭代自己的外部迭代器或类的接口。

接口摘要

Iterator extends Traversable {

/* 方法 */

abstract public current ( ) : mixed

abstract public key ( ) : scalar

abstract public next ( ) : void

abstract public rewind ( ) : void

abstract public valid ( ) : bool

}

预定义迭代器

PHP 已经提供了一些用于日常任务的迭代器。详细列表参见 SPL 迭代器。

范例

Example #1 基本用法

这个例子展示了使用 foreach 时，迭代器方法的调用顺序。

<?phpclass myIterator implements Iterator { private $position = 0; private $array = array( "firstelement", "secondelement", "lastelement", ); public function __construct() { $this->position = 0; } function rewind() { var_dump(__METHOD__); $this->position = 0; } function current() { var_dump(__METHOD__); return $this->array[$this->position]; } function key() { var_dump(__METHOD__); return $this->position; } function next() { var_dump(__METHOD__); ++$this->position; } function valid() { var_dump(__METHOD__); return isset($this->array[$this->position]); }}$it = new myIterator;foreach($it as $key => $value) { var_dump($key, $value); echo "\n";}?>

以上例程的输出类似于：

string(18) "myIterator::rewind"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(0)
string(12) "firstelement"

string(16) "myIterator::next"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(1)
string(13) "secondelement"

string(16) "myIterator::next"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(2)
string(11) "lastelement"

string(16) "myIterator::next"
string(17) "myIterator::valid"

Php/docs/class.iterator

目录

简介

接口摘要

预定义迭代器

范例

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