Interfaces An interface is a contract: The person writing the interface says, “hey, I accept things looking that way“, and the person using the interface says “OK, the class I write looks that way“. An interface is an empty shell. There are only the signatures of the methods, which implies that the methods do not … Read more
A function is a piece of code that is called by name. It can be passed data to operate on (i.e. the parameters) and can optionally return data (the return value). All data that is passed to a function is explicitly passed. A method is a piece of code that is called by a name … Read more
Short Answer Use $this to refer to the current object. Use self to refer to the current class. In other words, use $this->member for non-static members, use self::$member for static members. Full Answer Here is an example of correct usage of $this and self for non-static and static member variables: <?php class X { private … Read more
The Inversion-of-Control (IoC) pattern, is about providing any kind of callback (which controls reaction), instead of acting ourself directly (in other words, inversion and/or redirecting control to external handler/controller). The Dependency-Injection (DI) pattern is a more specific version of IoC pattern, and is all about removing dependencies from your code. Every DI implementation can be … Read more
Variables declared inside the class definition, but not inside a method are class or static variables: >>> class MyClass: … i = 3 … >>> MyClass.i 3 As @millerdev points out, this creates a class-level i variable, but this is distinct from any instance-level i variable, so you could have >>> m = MyClass() >>> … Read more
super() lets you avoid referring to the base class explicitly, which can be nice. But the main advantage comes with multiple inheritance, where all sorts of fun stuff can happen. See the standard docs on super if you haven’t already. Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of … Read more