References
PHP reference
Learn server-side web programming basics.
PHP Basics
Print a value from a PHP script.
PHP Arrays
Loop through an indexed array.
PHP Functions
Declare typed parameters and return values.
PHP strings, sprintf, and regular expressions
Format text with sprintf, split and join strings, and match patterns with preg functions.
PHP strict types, match, and the nullsafe operator
Use union types, a match expression, constructor promotion, and ?-> to write safer code.
PHP closures, array functions, and generators
Transform arrays with map, filter, and reduce, capture variables in closures, and produce values lazily with yield.
PHP Classes
Hide a property and change it only through methods.
PHP interfaces, traits, and abstract classes
Share a contract with an interface, share code with a trait, and share both with an abstract base.
PHP Associative Arrays
Map names to values and loop over keys and values.
PHP sorting, usort, and the spaceship operator
Sort arrays by value or by custom rules, and combine several sort keys with <=>.
PHP SPL data structures: stack, queue, and heap
Use the standard SplStack, SplQueue, SplMinHeap, and SplPriorityQueue classes.
PHP unit tests with closures
Write a tiny test runner with named test closures and check normal values and expected errors.
PHP password_hash, password_verify, and hash_hmac
Store passwords with bcrypt through the built-in API and sign messages with HMAC.
PHP preventing XSS with htmlspecialchars
Encode user text before printing it into HTML, and escape for the right context.