spl | 易学教程

PHP SPL笔记

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PHP SPL笔记作者：阮一峰日期： 2008年7月 8日这几天，我在学习PHP语言中的 SPL 。这个东西应该属于PHP中的高级内容，看上去很复杂，但是非常有用，所以我做了长篇笔记。不然记不住，以后要用的时候，还是要从头学起。由于这是供自己参考的笔记，不是教程，所以写得比较简单，没有多解释。但是我想，如果你是一个熟练的PHP5程序员，应该足以看懂下面的材料，而且会发现它很有用。现在除此之外，网上根本没有任何深入的SPL中文介绍。 ================ PHP SPL笔记目录第一部分简介 1. 什么是SPL？ 2. 什么是Iterator？第二部分 SPL Interfaces 3. Iterator界面 4. ArrayAccess界面 5. IteratorAggregate界面 6. RecursiveIterator界面 7. SeekableIterator界面 8. Countable界面第三部分 SPL Classes 9. SPL的内置类 10. DirectoryIterator类 11. ArrayObject类 12. ArrayIterator类 13. RecursiveArrayIterator类和RecursiveIteratorIterator类 14. FilterIterator类 15.

RecursiveFilterIterator re-instantiated within RecursiveIteratorIterator?

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问题 The standard way to recursively scan directories via SPL iterators is: $files = new RecursiveIteratorIterator( new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::CHILD_FIRST ); foreach ($files as $file) { print $file->getPathname() . PHP_EOL; } I want a composable set of filters to apply to my recursive file search. I'm using a RecursiveDirectoryIterator to scan a directory structure. I want to apply more than one filter to my directory structure. My set up code: $filters = new

Get all parent nodes with RecursiveArrayIterator

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问题 Essentially, I want to use the $foo = new RecursiveIteratorIterator(new RecursiveArrayIterator($haystack)); Methodology, but instead of returning a flat array for foreach() ing through, keep the structure but only return a single great-grand-child node and it's parent nodes. Is this possible in PHP? I've been tasked with optimising some of my company's (horrific) codebase. I found a function that recurses through an array, searching for a key. I can't replace this with a simple array_search()

Build U-Boot SPL for custom board

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问题 I have built a custom board with a iMX6 Processor. Unfortunately i have not stripped out the Bootloader Config pins. They are still unconnected BGA-Balls. I do have access to UART1-3, JTAG and SD-Card interface and also to the BOOT0 and BOOT1 pins. No i would like to start a U-Boot. Therefore i have ported or added my own board to the configs. I can build U-Boot successfull (not tested on the board yet). Then i thought, i could download u-boot into the internal RAM of the i.MX6. unfortunately

PHP, SPL, ArrayAccess Interface

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问题 I am trying to understand the idea behind ArrayAccess Interface, I dont understand what each method is about, If those methods(functions) are "built in" functions and ArrayAccess Interface(also "built in") is only "make sure" i am going to implement those "built in" methods(functions) I am trying to understand what does each of thoes functions is doing with our code "Behind the scenes". function offsetSet($offset, $value); function offsetGet($offset); function offsetUnset($offset); function

How SplPriorityQueue works when priority is not an integer?

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问题 I was wondering how SplPriorityQueue works when priority is string or int . Quick example: $queue = new \SplPriorityQueue(); $queue->insert('b', 5); $queue->insert('c', 5); $queue->insert('d', 1); $queue->insert('a', 10); $queue->insert('1', 'a'); $queue->insert('2', 'b'); print_r($queue); Output: Array ( [5] => a [4] => b [3] => c [2] => d [1] => 2 [0] => 1 ) Question : why items with int priority are listed first (i.e. a b c d)? When priority is string (items 1 2), is b considered greater

Extending ArrayObject in PHP properly?

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问题 Problem: I am trying to extend PHP's ArrayObject as shown below. Unfortunately I can't get it to work properly when setting multi-dimensional objects and instead an error thrown as I have the strict settings enabled in PHP. ( Error: Strict standards: Creating default object from empty value ) Question: How can I modify my class to automatically create non-existing levels for me? The code: $config = new Config; $config->lvl1_0 = true; // Works $config->lvl1_1->lvl2 = true; // Throws error as

Is it possible to use SplEnum in php 5.2.6?

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问题 I tried to use class : abstract class my_abstractEnum extends SplEnum { ... } and class my_categoryEnum extends my_abstractEnum { ... } and I have : Fatal error: Class 'SplEnum' not found I work on PHP 5.2.6. SplEnum is for php > 5.3 ? I don't see so in the documentation ... 回答1: SplTypes is an experimental PECL Extension. You have to install it with pecl install SPL_Types from the command line. There is no DLL for windows, so you are limited to Linux (or have to build your own). An

memory leak while processing large CSV

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问题 I have a script that downloads a large product CSV file, processes the information therein (downloading images and resizing and preparing other data for database insertion), then creates another txt file of all the processed items. The problem is that it seems to be hemmoraging memory somewhere. I get an error 500 returned, but the log shows too much memory usage. I've unset as much as I can, and I'm using SPL iterators which are supposed to be less memory intensive, but i still can get to

【PHP高级特性】自动加载

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前言： include 和 require 是PHP中引入文件的两个基本方法。在小规模开发中直接使用 include 和 require 没哟什么不妥，但在大型项目中会造成大量的 include 和 require 堆积。这样的代码既不优雅，执行效率也很低，而且维护起来也相当困难。为了解决这个问题，部分框架会给出一个引入文件的配置清单，在对象初始化的时候把需要的文件引入。但这只是让代码变得更简洁了一些，引入的效果仍然是差强人意。PHP5 之后，随着 PHP 面向对象支持的完善，__autoload 函数才真正使得自动加载成为可能。 * include 和 require 功能是一样的，它们的不同在于 include 出错时只会产生警告，而 require 会抛出错误终止脚本。 * include_once 和 include 唯一的区别在于 include_once 会检查文件是否已经引入，如果是则不会重复引入。 1、自动加载 __autoload（废弃）实现自动加载最简单的方式就是使用 __autoload 魔术方法。当需要使用的类没有被引入时，这个函数会在PHP报错前被触发，未定义的类名会被当作参数传入。至于函数具体的逻辑，这需要用户自己去实现。首先创建一个 autoload.php 来做一个简单的测试： // 类未定义时，系统自动调用function _