Core Python Programming

13.8. Composition

Once a class is defined, the goal is to use it as a model programmatically, embedding this object throughout your code, intermixing use with other data types and the logical flow of execution. There are two ways of utilizing classes in your code. The first is composition. This is where different classes are mingled with and into other classes for added functionality and code reusability. You may perhaps create instances of your class inside a larger class, containing other attributes and methods enhancing the use of the original class object. The other way is with derivation and discussed in the next section.

For example, let us imagine an enhanced design of the address book class we created at the beginning of the chapter. ...