CachingIterator::CALL_TOSTRING: Convert every element to string.
CachingIterator::CATCH_GET_CHILD: Don't throw exception in accessing children.
CachingIterator::TOSTRING_USE_KEY: Use key for conversion to string.
CachingIterator::TOSTRING_USE_CURRENT: Use current for conversion to string.
CachingIterator::TOSTRING_USE_INNER: Use inner for conversion to string.
CachingIterator::FULL_CACHE: Cache all read data.

更新日志

版本	说明
8.0.0	CachingIterator implements Stringable now.

CachingIterator::__construct — Construct a new CachingIterator object for the iterator
CachingIterator::count — The number of elements in the iterator
CachingIterator::current — Return the current element
CachingIterator::getCache — Retrieve the contents of the cache
CachingIterator::getFlags — Get flags used
CachingIterator::getInnerIterator — Returns the inner iterator
CachingIterator::hasNext — Check whether the inner iterator has a valid next element
CachingIterator::key — Return the key for the current element
CachingIterator::next — Move the iterator forward
CachingIterator::offsetExists — The offsetExists purpose
CachingIterator::offsetGet — The offsetGet purpose
CachingIterator::offsetSet — The offsetSet purpose
CachingIterator::offsetUnset — The offsetUnset purpose
CachingIterator::rewind — Rewind the iterator
CachingIterator::setFlags — The setFlags purpose
CachingIterator::__toString — Return the string representation of the current element
CachingIterator::valid — Check whether the current element is valid

add a note

User Contributed Notes 4 notes

down

ahmad dot mayahi at gmail dot com ¶

2 years ago


The only difference between CachingIterator and other Iterators such as ArrayIterator is the hasNext() method.

Since the data will be loaded into the memory, the CachingIterator is able to check whether the given iterator has a next element.

Let's demonstrate this by an example:

<?php
$iterator = new CachingIterator(new ArrayIterator(['C', 'C++', 'C#', 'PHP', 'Python', 'Go', 'Ruby']));

foreach ($iterator as $item) {
    if ($iterator->hasNext()) {
        echo $item.', ';
    } else {
        echo 'and '.$item;
    }
}

// C, C++, C#, PHP, Python, Go, and Ruby
?>

In this example I check whether the iterator has a next value, if so, I append a comma otherwise "and" will be appended to the last element.

down

ahmad dot mayahi at gmail dot com ¶

5 years ago


<?php
//This snippet will print out all the cached elements (foreach) .

$cache  = new CachingIterator(new ArrayIterator(range(1,100)), CachingIterator::FULL_CACHE);

foreach ($cache as $c) {

}

print_r($cache->getCache());
?>

down

jerome at chaman dot ca ¶

2 years ago


"cached iteration over another iterator" means this iterator is always one step behind the inner iterator. In other words, the "first" iteration will yield null:

<?php

$cit = new CachingIterator( new ArrayIterator( [ 'a', 'b', 'c']  ) );

echo $cit->current() ); // null
echo $cit->getInnerIterator()->current() ); // "a"

while($cit->hasNext()){
    
    // we start with a "next" since the "first" item is null
     $cit->next();
     echo $cit->current(), '<br>';
   
}
?>

iterating this way gives us an access, ahead, to the future item (aka current item of the inner iterator)

down

xedin dot unknown at gmail dot com ¶

2 years ago


Apparently, the `FULL_CACHE` flag automatically cancels the default flag `CALL_TOSTRING`. This is evident when one of the values cannot be converted to string: with the default `CALL_TOSTRING` flag, it would throw an error; without that flag, or with the `FULL_CACHE` flag, it does not.

add a note

官方地址：https://www.php.net/manual/en/class.cachingiterator.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 科技开发编程 Elasticsearch HTML/CSS/XML 网络 JAVA NoSQL C/C++ 面试 Golang 数据库 Git 算法正则表达式操作系统 Redis 互联网 MySql JavaScript 运维软件架构设计 Mac OS TCP/IP 国际 Excel Vim Windows Socket Oracle VR MongoDB 运营 Python MemCache 商业硬件电子设计 nginx 娱乐摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 [PHP] inet_pton/inet_ntop IP地址转换函数 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 PHPMailer设置utf8 PHPMailer字符集CharSet 如何在Composer中为GitLab实例设置访问令牌 array_multisort() 多字段排序 laravel框架查看sql语句方式 [原创]诡异的php-fpm超时问题 PHP获取指定函数定义在哪个文件中及行号利用php soap实现web service php设置cookie为httponly防止xss攻击 PHP-FPM进程数的设定 PHP5 扩展SOAP 调用 webservice PHP7添加redis扩展 adodb手册利用PHP SOAP实现WEB SERVICE ADOConnection 公用函数 php上周一、本周一、下周一日期 Composer的Packagist资源

略微加速

PHP官方手册 - 互联网笔记

The CachingIterator class

简介

类摘要

预定义常量

更新日志

目录

User Contributed Notes 4 notes