国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Table of Contents
The Implementation of PHP Arrays at the C Level
Home Backend Development PHP Tutorial Why are Some PHP Array Functions Slow, and How Does the C-Level Implementation Affect Their Performance?

Why are Some PHP Array Functions Slow, and How Does the C-Level Implementation Affect Their Performance?

Nov 03, 2024 pm 01:19 PM

Why are Some PHP Array Functions Slow, and How Does the C-Level Implementation Affect Their Performance?

The Implementation of PHP Arrays at the C Level

Understanding PHP Array Performance

PHP arrays are extensively used in PHP programming, offering various functionalities and flexibility. However, it has been noticed that certain array_* functions exhibit slow performance, particularly when working with large arrays.

C-Level Implementation of PHP Arrays

To gain insights into the performance bottleneck, it is essential to understand the C-level implementation of PHP arrays. After examining the zend/zend_hash.h and ext/standard/array.c files, it is discovered that PHP arrays are implemented as:

  • Chained hash tables
  • Allowing both string and integer keys
  • Employing two different hashing algorithms for key space allocation

Each entry in the hash table is linked to its preceding and succeeding values, forming linked lists. Additionally, a temporary pointer is used to keep track of the current item for iteration.

Performance Analysis

The slow performance of array_rand is attributed to its design, which ensures true randomness by iterating over the array rand(0, count($array)) times. This is necessary because it is not possible to access offsets in the hash table in O(c) time, as there could be missing keys within the range.

Another performance consideration is the difference between array_key_exists and in_array. While array_key_exists uses hash lookup for key checking (mostly O(c)), in_array employs linear search (O(n)), potentially resulting in lower performance for large arrays.

Conclusion

Despite their flexibility, PHP arrays do not have a data type that exhibits the characteristics of traditional C arrays. While hash lookups are generally faster, their limitations become apparent in certain scenarios, such as array_rand. This highlights the need for careful consideration of the array implementation when optimizing code performance.

The above is the detailed content of Why are Some PHP Array Functions Slow, and How Does the C-Level Implementation Affect Their Performance?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to set PHP time zone? How to set PHP time zone? Jun 25, 2025 am 01:00 AM

TosettherighttimezoneinPHP,usedate_default_timezone_set()functionatthestartofyourscriptwithavalididentifiersuchas'America/New_York'.1.Usedate_default_timezone_set()beforeanydate/timefunctions.2.Alternatively,configurethephp.inifilebysettingdate.timez

What are the best practices for writing clean and maintainable PHP code? What are the best practices for writing clean and maintainable PHP code? Jun 24, 2025 am 12:53 AM

The key to writing clean and easy-to-maintain PHP code lies in clear naming, following standards, reasonable structure, making good use of comments and testability. 1. Use clear variables, functions and class names, such as $userData and calculateTotalPrice(); 2. Follow the PSR-12 standard unified code style; 3. Split the code structure according to responsibilities, and organize it using MVC or Laravel-style catalogs; 4. Avoid noodles-style code and split the logic into small functions with a single responsibility; 5. Add comments at key points and write interface documents to clarify parameters, return values ??and exceptions; 6. Improve testability, adopt dependency injection, reduce global state and static methods. These practices improve code quality, collaboration efficiency and post-maintenance ease.

How do I execute SQL queries using PHP? How do I execute SQL queries using PHP? Jun 24, 2025 am 12:54 AM

Yes,youcanrunSQLqueriesusingPHP,andtheprocessinvolveschoosingadatabaseextension,connectingtothedatabase,executingqueriessafely,andclosingconnectionswhendone.Todothis,firstchoosebetweenMySQLiorPDO,withPDObeingmoreflexibleduetosupportingmultipledatabas

How to quickly test PHP code snippets? How to quickly test PHP code snippets? Jun 25, 2025 am 12:58 AM

ToquicklytestaPHPcodesnippet,useanonlinePHPsandboxlike3v4l.orgorPHPize.onlineforinstantexecutionwithoutsetup;runcodelocallywithPHPCLIbycreatinga.phpfileandexecutingitviatheterminal;optionallyusephp-rforone-liners;setupalocaldevelopmentenvironmentwith

How do I use page caching in PHP? How do I use page caching in PHP? Jun 24, 2025 am 12:50 AM

PHP page caching improves website performance by reducing server load and speeding up page loading. 1. Basic file cache avoids repeated generation of dynamic content by generating static HTML files and providing services during the validity period; 2. Enable OPcache to compile PHP scripts into bytecode and store them in memory, improving execution efficiency; 3. For dynamic pages with parameters, they should be cached separately according to URL parameters, and avoid cached user-specific content; 4. Lightweight cache libraries such as PHPFastCache can be used to simplify development and support multiple storage drivers. Combining these methods can effectively optimize the caching strategy of PHP projects.

How to upgrade PHP version? How to upgrade PHP version? Jun 27, 2025 am 02:14 AM

Upgrading the PHP version is actually not difficult, but the key lies in the operation steps and precautions. The following are the specific methods: 1. Confirm the current PHP version and running environment, use the command line or phpinfo.php file to view; 2. Select the suitable new version and install it. It is recommended to install it with 8.2 or 8.1. Linux users use package manager, and macOS users use Homebrew; 3. Migrate configuration files and extensions, update php.ini and install necessary extensions; 4. Test whether the website is running normally, check the error log to ensure that there is no compatibility problem. Follow these steps and you can successfully complete the upgrade in most situations.

Steps to configure a PHP development environment on Linux Steps to configure a PHP development environment on Linux Jun 30, 2025 am 01:57 AM

TosetupaPHPdevelopmentenvironmentonLinux,installPHPandrequiredextensions,setupawebserverlikeApacheorNginx,testwithaPHPfile,andoptionallyinstallMySQLandComposer.1.InstallPHPandextensionsviapackagemanager(e.g.,sudoaptinstallphpphp-mysqlphp-curlphp-mbst

PHP beginner guide: Detailed explanation of local environment configuration PHP beginner guide: Detailed explanation of local environment configuration Jun 27, 2025 am 02:09 AM

To set up a PHP development environment, you need to select the appropriate tools and install the configuration correctly. ①The most basic PHP local environment requires three components: the web server (Apache or Nginx), the PHP itself and the database (such as MySQL/MariaDB); ② It is recommended that beginners use integration packages such as XAMPP or MAMP, which simplify the installation process. XAMPP is suitable for Windows and macOS. After installation, the project files are placed in the htdocs directory and accessed through localhost; ③MAMP is suitable for Mac users and supports convenient switching of PHP versions, but the free version has limited functions; ④ Advanced users can manually install them by Homebrew, in macOS/Linux systems

See all articles