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이 문서에서는 PHP 중국어 웹사이트 매뉴얼 풀어 주다
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检测一个类是否可以使用 foreach 进行遍历的接口。
无法被单独实现的基本抽象接口。相反它必须由 IteratorAggregate 或 Iterator 接口实现。
Note:
实现此接口的内建类可以使用 foreach 进行遍历而无需实现 IteratorAggregate 或 Iterator 接口。
Note:
这是一个无法在 PHP 脚本中实现的内部引擎接口。IteratorAggregate 或 Iterator 接口可以用来代替它。
这个接口没有任何方法,它的作用仅仅是作为所有可遍历类的基本接口。
[#1] ajf at ajf dot me [2014-12-23 00:22:49]
Note that all objects can be iterated over with foreach anyway and it'll go over each property. This just describes whether or not the class implements an iterator, i.e. has custom behaviour.
[#2] kevinpeno at gmail dot com [2010-08-02 10:06:38]
While you cannot implement this interface, you can use it in your checks to determine if something is usable in for each. Here is what I use if I'm expecting something that must be iterable via foreach.
<?php
if( !is_array( $items ) && !$items instanceof Traversable )
//Throw exception here
?>