spl | 易学教程

Laravel Composer自动加载机制

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 大纲 PHP 自动加载功能 1.1 PHP 自动加载功能的由来 1.2 PHP 自动加载函数 __autoload() 1.3 __autoload() 函数存在的问题 1.4 SPL Autoload PSR 规范 comoposer 的自动加载过程 composer 源码分析 4.1 启动 4.2 Composer自动加载文件 1, PHP 自动加载功能 1.1 PHP 自动加载功能的由来在 PHP 开发过程中，如果希望从外部引入一个 Class ，通常会使用 include 和 require 方法，去把定义这个 Class 的文件包含进来。这个在小规模开发的时候，没什么大问题。但在大型的开发项目中，使用这种方式会带来一些隐含的问题：如果一个 PHP 文件需要使用很多其它类，那么就需要很多的 require/include 语句，这样有可能会造成遗漏或者包含进不必要的类文件。如果大量的文件都需要使用其它的类，那么要保证每个文件都包含正确的类文件肯定是一个噩梦，况且 require或 incloud 的性能代价很大。 PHP5 为这个问题提供了一个解决方案，这就是类的自动加载(autoload)机制。 autoload机制可以使得 PHP 程序有可能在使用类时才自动包含类文件

PHP SPL RegexIterator how files would be ordered?

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问题 Let's say I have a snippet: <?php $directoryIterator = new RecursiveDirectoryIterator('some_dir_here'); $iteratorIterator = new RecursiveIteratorIterator($directoryIterator); $regexp = '/hello_world[\d]*/'; $fileList = new RegexIterator($iteratorIterator, $regexp); foreach ($fileList as $file) { echo $file . PHP_EOL; } It gets all files from some_dir_here , which match regexp. How would be files in $fileList ordered (for example: by name ascending)? Are there any proofs in official docs? 回答1:

Iterate multidimensional Array recursively and return same array structure and inserting new key/values in PHP

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问题 I am trying to write a snippet that takes an multidimensional array and inserts some keys at the same level where a named search key is found. I don't have to rely on the structure of the array (but will be at most 5 levels) I can't use passing by reference so a traditional recurring function won't help with that approach. I have 2 options: SPL or a recursion that re-constructs the array and alters it along the way with SPL I can't seem to Insert a new value.. $a= new \ArrayObject(

Php, Spl, ArrayIterator

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问题 I am trying to understand piece of code: $array = array('koala', 'kangaroo', 'wombat', 'wallaby', 'emu', 'kiwi', 'kookaburra', 'platypus'); $object = new ArrayIterator($array); foreach($object as $key=>$value) { if($object->offSetGet($key) === 'kiwi') { $object->offSetUnset($key); } echo $key.' - '.$value."<br />"; } What i was trying to understand is why offSetUnset is taking the pointer to the second element at the array and not to the first one, My theory is the following sequence of

When does the NoRewindIterator rewind the inner Iterator?

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问题 By its name it is perfectly clear when PHP's NoRewindIterator rewinds: never. But sometimes, esp. when extending from it, I ask myself: Does it ever rewind? Does it rewind once? So if I need it, do I need to implement the (first) rewind as some Traversable might require it? I specifically wonder about the inner iterator here, so the Iterator the NoRewindIterator class takes as parameter with its constructor. For example: $iterator = new SomeIterator(); // implements Iterator $noRewind = new

How to serialize large objects/arrays to JSON

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问题 My app needs to produce json of an object that has a large data property of type array. The array needs to remain in memory as it collects DB output and some properties can only be determined once the array is completed. Complication: the array is numerically-based and must appear as such in the json output, therefore straight json_encode() is not an option. To make this possible on low-spec machines like RasPi I've looked into trimming memory consumption: Use SPLFixedArray Use string and

How can I sort arrays and data in PHP?

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问题 This question is intended as a reference for questions about sorting arrays in PHP. It is easy to think that your particular case is unique and worthy of a new question, but most are actually minor variations of one of the solutions on this page. If your question is closed as a duplicate of this one, please ask for your question to be reopened only if you can explain why it differs markedly from all of the below. How do I sort an array in PHP? How do I sort a complex array in PHP? How do I

PHP RecursiveIterator traversing

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问题 I have a structure representing a form and I want to iterate it using RecursiveIterator. The problem is this only returns the top-level questions. What am I doing wrong? Whole form: class Form implements RecursiveIterator{ private $id; private $caption; private $other_text; private $questions = array(); private $current; private function __construct(DibiRow $row){ $this->id = $row->id; $this->caption = $row->caption; $this->other_text = $row->other_text; $this->loadQuestions(); } private

spl_object_hash for PHP < 5.2 (unique ID for object instances)

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问题 I'm trying to get unique IDs for object instances in PHP 5+. The function, spl_object_hash() is available from PHP 5.2 but I'm wondering if there is a workaround for older PHP versions. There are a couple of functions in the comments on php.net but they're not working for me. The first (simplified): function spl_object_hash($object){ if (is_object($object)){ return md5((string)$object); } return null; } does not work with native objects (such as DOMDocument), and the second: function spl

Scrapy框架的使用之Scrapy对接Splash

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之前我们实现了Scrapy对接Selenium抓取淘宝商品的过程，这是一种抓取JavaScript动态渲染页面的方式。除了Selenium，Splash也可以实现同样的功能。本节我们来了解Scrapy对接Splash来进行页面抓取的方式。一、准备工作请确保Splash已经正确安装并正常运行，同时安装好Scrapy-Splash库。二、新建项目首先新建一个项目，名为scrapysplashtest，命令如下所示： scrapy startproject scrapysplashtest 新建一个 Spider，命令如下所示： scrapy genspider taobao www.taobao.com 三、添加配置可以参考Scrapy-Splash的配置说明进行一步步的配置，链接如下：https://github.com/scrapy-plugins/scrapy-splash#configuration。修改settings.py，配置 SPLASH_URL 。在这里我们的Splash是在本地运行的，所以可以直接配置本地的地址： SPLASH_URL = 'http://localhost:8050' 如果Splash是在远程服务器运行的，那此处就应该配置为远程的地址。例如运行在IP为120.27.34.25的服务器上，则此处应该配置为： SPLASH_URL =