spl | 易学教程

Android: record decibel from microphone

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问题 i've got problem on implementing this functionality in Android... i need only to output the decibel redorded from the microphone, and it's a thing that i can't understand: public class Noise extends Activity{ @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); MediaRecorder recorder=new MediaRecorder(); recorder.setAudioSource(MediaRecorder.AudioSource.MIC); Timer timer=new Timer(); timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500); }

Need iterator advice to traverse tree

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问题 Hi I need some iterator advice. I have a Category object which can contain a collection of items and also can have children categories. From doctrine ORM I do get a collection of category objects. Now I want to traverse this collection and flatten the category tree structure. So the children categories are at the same level as it's parent. I would also like to filter the children. Maybe somebody can point me in the right direction, currently a bit lost in the Iterator cloud. <?php class

Autoloaders in PHP - two running at a time

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问题 I understand how to register autoloaders and even how to create one, that's no issue at all. How ever the main issue is - how do you have two auto loaders running side by side for something like: class project_one_folder_class extends project_two_folder_class{} You'll notice that the child class belongs to a project which is reaching out and calling the parent class which is locate in a different project. The way the projects are linked project two's classes are always seen by the auto loader

PHP-自动加载原理分析

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说起PHP的自动加载，很多同学可能都会想到各种框架的自动加载功能，PHP规范中的PSR0和PSR4原则，Composer的自动加载功能等等，这些都为我们的开发提供了很大的方便。那么PHP自动加载的前因后果到底是什么？PHP的内部原理又是怎么样的呢？接下来我就根据自己的理解进行一下分析总结：为什么会有自动加载？在PHP面向对象(OO)编程中，为了方便管理，我们都会把一个类写在一个单独的文件中，那么如果想在A类中使用B类的功能，就需要把B类加载到A类。对于这样的需求在最原始的时候，我们是通过require 和 include 语法实现的，这2种语法结果基本一样，执行流程有一些区别，这里不解释。例如： //文件 B.php <?php class B { public function echo_info () { echo "我是class B中的方法执行结果" ; } } ?> //文件 A.php <?php require 'b.php' ; //include 'b.php'; class A { public function test () { $b_object = new B(); $b_object ->echo_info(); } } $a_object = new A(); $a_oject ->test(); ?> 命令行输入： #php a.php 输出

What is the point of PHP's SplDoublyLinkedList class, and more importantly, Linked Lists in general?

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问题 On a quest to expand my programming prowess, I've delved ever-so-slightly into The Standard PHP Library. This led to my discovery of the SplDoublyLinkedList class. From there I read the descriptions of Linked Lists and Doubly Linked Lists on Wikipedia. I understand how they work... But I cannot conceive of a reason WHY we need it—or better yet a practical example of SplDoublyLinkedList since we have indexed and associative arrays in PHP. How are Linked Lists normally used in-and-out of PHP?

Autoloaders in PHP - two running at a time

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I understand how to register autoloaders and even how to create one, that's no issue at all. How ever the main issue is - how do you have two auto loaders running side by side for something like: class project_one_folder_class extends project_two_folder_class{} You'll notice that the child class belongs to a project which is reaching out and calling the parent class which is locate in a different project. The way the projects are linked project two's classes are always seen by the auto loader, how ever project one's classes are never seen. So the way I thought around this was to write two auto

SPL vs. Array: When should we use SPL and when should we use Array in PHP?

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问题 In java and C++ when we don't know the size - array not used like in PHP, instead used linkedList etc. In PHP exist SPL, but most of the times programmers use array, why (because people don't know about SPL )? When we should use Array in PHP and whenSPL and what is the difference in this case between PHP and Java/C++? 回答1: Every PHP request must initialize all variables and after request they are freed. Because of that not often comes situations where special data structures (like maxheap,

RecursiveFilterIterator re-instantiated within RecursiveIteratorIterator?

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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: $filters = new FilterRuleset( new RecursiveDirectoryIterator($path) ); $filters->addFilter(new FilterLapsedDirs);

PHP spl_autoload_register()函数的一些见解

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由于公司网络完全禁掉了一切可以翻墙的可能（中国电信内部）。无奈只能使用百度查spl_autoload_register（）一些详细信息，因为该函数在手册上面说是可以注册多个__autoload()，而且可以都能作用。我很好奇这个是怎么做到的，毕竟__autoload()就只能注册一种机制，为何spl_autoload_register（）就可以使用多种机制了呢？(我以后再也不会使用百度来浪费我的时间了！) 感谢stackoverflow上面的Sep网友：http://stackoverflow.com/questions/3710480/php-spl-autoload-register。其中这句： For example, if your most commonly used classes are in services, then vos, then printers, the order you have is perfect. This is because they're queued and called in-order, so you'll achieve slightly better performance by doing this. 解释了这个函数的一个机制。如手册所说的一样，这个是一个堆栈式的函数机制

P3391 【模板】文艺平衡树

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题目链接： #include <bits/stdc++.h> using namespace std; #define ll long long #define re register const int N=1e6+10; void read(int &a) { a=0;int d=1;char ch; while(ch=getchar(),ch>'9'||ch<'0') if(ch=='-') d=-1; a=ch^48; while(ch=getchar(),ch>='0'&&ch<='9') a=(a<<3)+(a<<1)+(ch^48); a*=d; } struct note{int ch[2],siz,tag,cnt,val,fa;}spl[N]; int rt,cnt,n,m; void newnode(int &now,int fa,int val) { spl[now=++cnt].val=val; spl[now].siz=spl[now].cnt=1; spl[now].fa=fa; spl[now].tag=0; } int ident(int x,int f){return spl[f].ch[1]==x;}///判断是否为右儿子 void connect(int x,int f,int s) { spl[f].ch[s]=x; spl[x].fa=f;