PHP (Core & OOP)

An interface can only contain method signatures (no implementation), and a class can implement multiple interfaces. An abstract class can have both signatures and implementations, but a class can only inherit from one abstract class.

Traits are a mechanism for code reuse. A trait is similar to a class, but it is purely intended to group functionality in a fine-grained and consistent way. They allow developers to reuse sets of methods freely in several independent classes, overcoming single inheritance limitations in PHP.

Late static binding is used to reference the called class in a context of static inheritance using the `static::` keyword, rather than `self::` which refers to the class where the method is defined.

By using Prepared Statements (PDO or MySQLi), filtering inputs, and escaping outputs, rather than directly concatenating variables into SQL strings.

The '==' operator checks for value equality, while the '===' operator checks for both value and type equality.

Inheritance in PHP is implemented using the 'extends' keyword, which allows a child class to inherit properties and methods from a parent class.

The 'final' keyword is used to prevent a method from being overridden in a child class or to prevent a class from being inherited.

'public' members can be accessed from anywhere, 'private' members can only be accessed within the same class, and 'protected' members can be accessed within the same class and its child classes.

Polymorphism in PHP can be achieved through method overloading or method overriding, where multiple methods with the same name can be defined with different parameters or return types.

The '__construct' method is a special method in PHP that is automatically called when an object of a class is created, and is used to initialize the object's properties.

PHP provides a built-in exception handling mechanism using try-catch blocks, where the 'try' block contains the code that might throw an exception, and the 'catch' block contains the code that handles the exception.

The 'include' statement includes a file and generates a warning if the file is not found, while the 'require' statement includes a file and generates a fatal error if the file is not found.

The Singleton design pattern in PHP can be implemented using a class that has a private constructor, a private static instance, and a public static method that returns the instance.

The 'autoload' function in PHP is used to automatically include classes and interfaces when they are instantiated, without the need for explicit 'include' or 'require' statements.

PHP's 'ReflectionClass' can be used to get information about a class, such as its properties, methods, and constants, by creating an instance of the class and using its methods.

The 'foreach' loop is used to iterate over arrays, while the 'while' loop is used to iterate over a block of code as long as a certain condition is true.

PHP's 'Iterator' interface can be used to create custom iterators by implementing its methods, such as 'rewind', 'current', 'key', 'next', and 'valid'.

The 'namespace' keyword in PHP is used to group related classes, interfaces, and functions under a unique name, to avoid naming conflicts and improve code organization.

PHP's 'Closure' can be used to create anonymous functions by assigning a function to a variable without declaring a named function.

The 'serialize' function converts a PHP object into a serialized string, while the 'json_encode' function converts a PHP object into a JSON string.

PHP's 'SplFileObject' can be used to read and write files by creating an instance of the class and using its methods, such as 'read' and 'write'.

The 'magic methods' in PHP, such as '__get' and '__set', are special methods that are automatically called when certain actions are performed on an object, such as getting or setting a property.

PHP's 'ArrayObject' can be used to create objects that behave like arrays by creating an instance of the class and using its methods, such as 'offsetGet' and 'offsetSet'.

An 'abstract' class can contain both abstract and concrete methods, while an 'interface' can only contain abstract methods.

PHP's 'DateTime' class can be used to work with dates and times by creating an instance of the class and using its methods, such as 'format' and 'modify'.