PHP

Articles about PHP by topic. New to the language? Start with the basics or the course.

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Basics PHP basics What the language is, where it is used and what else it can do. Open Course PHP course: zero to hero PHP 8.5 lesson by lesson: language basics, OOP, web, quality tools and capstone projects. Open Functions Built-in functions of PHP 8.5 Every built-in function on its own page: signature, parameters, return value and an example. Open Versions PHP versions: history in brief What each major version changed, with details on PHP 8.0 and PHP 8.5. Open

Language

Arrays Arrays in PHP How to create an array and read its elements. Open Comments Comments in PHP One-line and multi-line comments. Open Ternary Ternary operator A short if-else in one expression. Open OOP OOP in PHP Classes, objects, constructors, visibility and static members. Open Namespaces Namespaces in PHP One short class name, many classes: namespace, use and aliases. Open require require and include require, require_once, include, include_once: differences, traps and a safe-include checklist. Open External Call a function from another file How to use a function defined in another PHP file. Open Dedup Deduplication in PHP array_unique, require_once, function_exists guards, DISTINCT and UNIQUE. Open Pitfalls Flat pair arrays: three pitfalls What goes wrong with a flat [url, title] array and how to guard against it. Open

Dates, numbers and data

DateTime Date and time in PHP How to print date and time in different formats. Open Timezones Several timezones on one page How to show the time of several timezones at once. Open Dates Compare two dates How to find out which of two dates is earlier. Open random_int Unique random numbers How to generate random numbers that do not repeat. Open json_decode json_decode How to turn a JSON string into PHP arrays and objects. Open

Web

Cookies Cookies How to set, read and delete cookies, with examples. Open Sessions PHP sessions How sessions work and how to keep data between requests. Open Auth Authentication and authorization How to authenticate users and services in PHP. Open Databases Databases with PHP How to connect to a database and run queries. Open REST API REST API requests How to send requests to a REST API from PHP. Open URL Insert a variable into a link How to put the value of a variable into a URL. Open User-Agent HTTP_USER_AGENT How to find out the User-Agent of a visitor. Open Screen Screen width with PHP What PHP can and cannot tell about the screen of a visitor. Open .htaccess Rules in .htaccess Redirect, RedirectMatch and RewriteRule: which rules are safe on which server. Open

Errors and tools

Errors PHP errors: case studies Real debugging cases: a menu that disappeared, a live page cut short. Open Chunk Premature end of chunk coded message body Why the "closing chunk expected" error appears. Open Linters PHP linters we use php -l, PHPCS, PHPCBF, PHPStan and Psalm on this site. Open

Frameworks

Laravel Laravel What Laravel is and a course of 50 lessons. Open Symfony Symfony What Symfony is and a course of 50 lessons. Open

Other sites

Elsewhere PHP articles on other sites Session locking, installing frameworks, profiling and XDebug. Open