


How Can I Replace Only the First (or Last) Occurrence of a Substring in PHP?
Replacing Only the First Occurrence with str_replace
While there's no built-in str_replace function that limits its replacement to the first occurrence, a relatively straightforward solution exists without resorting to intricate hacks.
To achieve this, utilize the strpos function to locate the position of the substring within the main string. Once identified, employ substr_replace to modify the original string, specifying the occurrence position and the length of the substring. This method efficiently replaces the first occurrence without the overhead of regular expressions.
Code Example:
$haystack = "This is a sample string"; $needle = "is"; $replace = "was"; $pos = strpos($haystack, $needle); if ($pos !== false) { $newstring = substr_replace($haystack, $replace, $pos, strlen($needle)); } echo $newstring; // Output: "This was a sample string"
Bonus: To replace the last occurrence, substitute strpos with strrpos:
$pos = strrpos($haystack, $needle); if ($pos !== false) { $newstring = substr_replace($haystack, $replace, $pos, strlen($needle)); }
The above is the detailed content of How Can I Replace Only the First (or Last) Occurrence of a Substring in PHP?. For more information, please follow other related articles on the PHP Chinese website!

The article explains how to create, implement, and use interfaces in PHP, focusing on their benefits for code organization and maintainability.

The article discusses the differences between crypt() and password_hash() in PHP for password hashing, focusing on their implementation, security, and suitability for modern web applications.

Article discusses preventing Cross-Site Scripting (XSS) in PHP through input validation, output encoding, and using tools like OWASP ESAPI and HTML Purifier.

Autoloading in PHP automatically loads class files when needed, improving performance by reducing memory use and enhancing code organization. Best practices include using PSR-4 and organizing code effectively.

PHP streams unify handling of resources like files, network sockets, and compression formats via a consistent API, abstracting complexity and enhancing code flexibility and efficiency.

The article discusses managing file upload sizes in PHP, focusing on the default limit of 2MB and how to increase it by modifying php.ini settings.

The article discusses nullable types in PHP, introduced in PHP 7.1, allowing variables or parameters to be either a specified type or null. It highlights benefits like improved readability, type safety, and explicit intent, and explains how to declar

The article discusses the differences between unset() and unlink() functions in programming, focusing on their purposes and use cases. Unset() removes variables from memory, while unlink() deletes files from the filesystem. Both are crucial for effec


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

SublimeText3 Chinese version
Chinese version, very easy to use

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

WebStorm Mac version
Useful JavaScript development tools

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
