Articles on Trending Technologies

Technical articles with clear explanations and examples

What is the meaning of a Persistent Cookie in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 1K+ Views

A persistent cookie is a cookie that is stored permanently on the user's computer and remains available even after the browser is closed. Unlike session cookies which are temporary and stored only in browser memory, persistent cookies are saved to the hard disk and can be accessed across multiple browser sessions. Creating Persistent Cookies in PHP To create a persistent cookie in PHP, you must set an expiration time using the setcookie() function. The cookie will persist until the specified expiration date ? Reading Persistent Cookies You can retrieve persistent cookie values ...

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What is .htaccess in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 8K+ Views

.htaccess is a configuration file for web servers running the Apache server software. When a .htaccess file is placed in a directory that is loaded via the Apache web server, the file is detected and executed by Apache. .htaccess files can be utilized to modify the setup of the Apache server software to enable additional functionality and features. We can use the .htaccess file for various configuration alterations in Apache web server software. Some common uses are listed below − ErrorDocuments Creating custom error pages allows us to show website visitors a friendly error message when a ...

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Program to find how many times a character appears in a string in PHP

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 2K+ Views

In PHP, you can count how many times each character appears in a string by converting the string into an array and iterating through it. This technique is useful for text analysis and character frequency counting. Example Here's how to count character occurrences in a string ? Output w appears 1 times e appears 2 times l appears 2 times c appears 1 times o appears 4 times m appears 1 times t appears 4 times u appears 1 times r appears 1 times i appears 2 times a appears 1 ...

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What is traits in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 3K+ Views

In PHP 5.4, traits were introduced to object-oriented programming to solve the limitations of single inheritance. A trait is similar to a class but is designed specifically for grouping methods in a fine-grained and reusable way. Unlike classes, traits cannot be instantiated directly − they must be used within classes using the use keyword. Syntax trait TraitName { // methods and properties } class ClassName { use TraitName; // class methods and properties } Example Here's how to define and use ...

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Is there any advantage to using __construct() instead of the class's name for a constructor in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 623 Views

Yes, there are several advantages to using the magic function __construct() instead of the class's name for constructors in PHP − The magic function __construct() was introduced in PHP 5.0. One advantage of using __construct() over ClassName() as a constructor is if you change the name of the class, you don't need to update the constructor which supports DRY (don't repeat yourself) concept. If you have a child class you can call parent::__construct() to call the parent constructor in an easy way. Old-style constructors (using class names) are deprecated in PHP 7.0 and removed in PHP 8.0, making ...

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What is dependency injection in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 13K+ Views

Dependency injection is a design pattern where objects receive their dependencies from external sources rather than creating them internally. This approach promotes loose coupling, improves testability, and makes code more maintainable by avoiding hard-coded dependencies. There are several approaches to inject dependencies into objects. Here are the most commonly used methods − Constructor Injection In this approach, dependencies are injected through the class constructor when the object is instantiated − Total skills: 3 Skills: PHP, JQUERY, AJAX Setter Injection In setter injection, dependencies are provided through setter methods ...

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How to Zip a directory in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 2K+ Views

We can use PHP's ZipArchive class to zip and unzip directories in PHP. As of PHP 5.3, this class is built-in. Windows users need to enable php_zip.dll in their php.ini file. Installation Note: Ensure the PHP Zip extension is enabled. On Windows, uncomment extension=zip in php.ini. On Linux, install with sudo apt-get install php-zip. Basic Directory Zipping Here's how to zip all files in a directory − Recursive Directory Zipping To zip directories with subdirectories, use this recursive function − Key Points ...

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What is singleton design concept in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 4K+ Views

Singleton Pattern ensures that a class has only one instance and provides a global point to access it. It ensures that only one object is available all across the application in a controlled state. Singleton pattern provides a way to access its only object which can be accessed directly without the need to instantiate the object of the class. Example Output connection created bool(true) Key Benefits The Singleton pattern offers several advantages − Memory efficiency: Only one instance exists throughout the application Global access: The instance can ...

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How To enable GZIP Compression in PHP?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 6K+ Views

GZIP compression is a simple, effective way to save bandwidth and speed up PHP applications by compressing content before sending it to the client. The mechanism works in three steps. How GZIP Compression Works Browser/Client Server 1. Request for file ...

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What does double question mark (??) operator mean in PHP ?

Alok Prasad
Alok Prasad
Updated on 15-Mar-2026 6K+ Views

PHP 7 introduced the double question mark (??) operator, known as the Null Coalescing Operator. This operator returns its first operand if it exists and is not NULL; otherwise, it returns its second operand. The null coalescing operator evaluates from left to right and can be chained together for multiple fallback values. It's particularly useful for providing default values when working with potentially undefined variables. Syntax $result = $variable ?? $default_value; Basic Example Here's how the null coalescing operator works with an undefined variable − 9 ...

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